Indeed, it wasn't China, or cheap online competition that killed Radio Shack. It was 1950's business practices in the 21st century that doomed them.
Disclaimer: I worked for Radio Shack in the mid 80's while I was in college, so some of this is personal experience
First of all, there was oversaturation - in my neighborhood alone, a small suburban area, NOT a major metropolitan area, we had TWO Radio Shack stores within walking distance of one another. I worked at one, my best friend at the other. Within a 20 minute drive of my home, there were at least 6 Radio Shack stores. Sometimes this worked out, at least for the company, as if we were out of stock of an item, we would call the other store and it wasn't really inconvenient for the customer to head over there. However, I have to wonder how often that customer then bothered coming back to our store. Of course, that worked both ways.
Second of all - the insane business operations. EVERY customer was written up by hand. We sold computers, for goodness sake. But no, all sales tickets were hand printed. Then at the end of the say we keyed all the day's receipts into the store computer. This was long after even smaller retailers had gone to electronic cash registers and so forth. Then they tried to ride the wave of charge cards, and set quotas on everyone to get x number of credit apps per shift. Never mind it was only good at Radio Shack (and really there never were a lot of truly high ticket items - a full computer system, or the higher end stereos was about it) and the interest rates were horrible even for the times. Remember the free battery of the month club? Whenever someone came in for their free battery, we were supposed to write up a sales ticket, getting their name and address, AND try to get them to fill out a credit application. 9 times out of 10, this just pissed off the customer. That other 1 out of 10, they understood we were just doing what we were told. They still didn't take the time for the credit app. The free battery thing was one of those "Oh hey, I'm walking past the Radio Shack, let me pop in and get my battery" things, they weren't in the store shopping, they came to pop in and pop right back out again, and here we were trying to delay them with a credit card application.
Thirdly - even by then, there was a distinct lack of product knowledge. There were exceptions among my coworkers, but most of them had no clue what they were selling. I don't claim to know everything, but I could talk intelligently about the electronic parts we sold, the computer systems, and stereos. We had one guy who knew pretty much all there was to know about hooking up phone equipment like autodialers and answering machines (this was just after it became legal in the US to connect your own equipment, add you own lines in your house, and competing long distance companies like MCI and Sprint were popping up). Others I worked with were just outright clueless, many times I overheard utter bullshit being spewed to a customer.
And other things - I worked at the store near home over the summer, then transferred to one closer to college once classes started up. At that store, my manager was big into audio and video, and knew what he was doing. He had pretty much every combination of receiver and speaker hooked up in our store, so a customer could put together what they thought they wanted, and give it a listen, and we could maybe steer them to better speakers, or whatever. One day the district manager came by and told the store manager in no uncertain terms that ONLY the stereo system featured in the monthly flyer was to be hooked up, nothing else, and he needed to take it all down before his next visit. We had 2 boxes full of coax splitters and amplifiers, RCA cables, speaker switches, etc. When inventory came around, the store manager took one look at the boxes full of random stuff and basically said the hell with it, we're not inventorying that and putting it back on the shelves. I ended up with a box full of bits that to this day I have not fully exhausted despite giving TV coax cables to various other people as well as using them myself. What's just funny about it all is that even a store like KMart had a display with all their (crappy) car stereos hooked to any of their (also crappy) speakers so you could listen to any combo you wanted. But not Radio Shack, oh no!
Oh yes, inventory - another horrible all night and into the next day manual process. The computer would print out inventory sheets, then we went around the store and counted. Marked counts on the sheets. All fine and dandy for big box items, but those pegboards full of electronic parts - and you know there was always a joker who put pack a pack of 1K resistors 4 back on the peg for 10K's. After all this, the numbers were then keyed back into the computer to generate the final inventory report. For the standalone stores or those in a strip mall, it was no big deal, because those stores could stay open as long as necessary, and open as early as necessary. But our store was in a mall. Mall leasing rules set an absolute time we could stay and get in, and also dictated that our gate had to be up and the store open to customers within a certain time of the mall opening or face fines. We had all sorts of tricks to get a jump on the inventory, like counting all the big stuff during the day. It wasn't like we were going to sell more than 1 of some stereo system in a day, so we just kept the completed sections behind the counter and if someone happened to sell one of those things, they just marked it off on the inventory sheet.
In my area, I was pretty much stuck. If Radio Shack didn't have an electronic component, I had little choice but to mail order. And mail order in those days (prior to working at Radio Shack - under 18, no credit cards, no checking account) meant giving my Mom the money, getting her to write me a check, and sending it off and waiting at least 2 weeks - 3-4 days for the order to reach the company, usually on the other side of the US, a week waiting for the check to clear, and another 3-4 days for the order to come back. There was one shop nearby that carried RCA components, which was great when I built my first computer, which was all 4000 series CMOS, so I could get a few spare chips, when I could convince my Mom to drive me over there. But they were not a full service component shop, they had very little else, and even the 4000 series parts, they didn't stock much, most of the time I went there and ordered something and then had to go back a week later to pick it up. In a metro area that hosted 6 universities and the ATT/Bell Labs and plant that built among other things the first 64Kb RAM chip, it was amazing there were no electronic component sellers, at least on a consumer level.