I think the question is not so much that ham radio is fading (it actually is making a very gradual recovery, at least in the US) but why it ever took off in the first place.
Think about it. When us old-timers got started in electronics there were typically no more than three categories of "electronic" devices in the house:
- one or more radios.
- one or more record players, possibly including radios. Maybe one of them in a "stereo console" in the living room.
- a TV set. ("Nobody has two TVs" - Marty McFly's grandmother)
The first thing most of us did was to make a "crystal set" - a radio receiver. A few of us built more complicated receivers, then got into ham radio - a natural extension.
At the time, a lot of us lived on property where we already had a TV antenna on a tall mast and if we put up a big ham antenna on a tower, the neighbors might complain a bit but they couldn't stop us.
Others got into home-built audio - an extension of the record player.
So now we have video games, home video, computers, and the internet. It's just a case of more directions to go with an interest in electronics.
The internet has collided with ham radio: We have digital modes, we have APRS, we have D-STAR, we have EchoLink and IRLP. I can key up my handheld 2m/440 transceiver and talk to people in many parts of the world (but mostly the western US), just by hitting my nearest "Winsystem" repeater. On the other hand, many more of us now live in apartments or in houses where HOAs prohibit outside antennas. (Or try to.) So HF, which needs big antennas, is definitely on the wane.
The microcomputer revolution has given us microcontrollers and op-amps that have opened up a *type* of hobby electronics to many people who just couldn't wrap their heads around analog (much past a simple one-transistor buffer stage, anyway) and who couldn't see slogging through minimization via Karnaugh maps to build things that need a state machine. And those things are getting used in ham radio, too. You can now run an IRLP node on a Raspberry Pi. For those who don't mind a little math, DSP opens up a whole new word of analog possibilities - not excluding radio receivers.
Things change, but that doesn't mean there isn't plenty of fun to be had.