Because you cant get a new pad to replace it with so it is dead and flogged . A replacement Ryobi with variable speed is about $70USD locally much as I would like the Bosch gear drive the extra $ are a bit tough to justify.
Do you get free sunglasses with it to protect you from the vile green glare for that $70? :-)
Lucky I am colourblind and not prejudiced I can buy a DeWalt (colour is no better) or a Makita for over twice the price at the localish store.
My current favourite make, based on past performance of things I've owned for a long time, is Makita - even if they do come in a rather disgusting teal colour. I have a small Ryobi driver, which has worked well for the seven years I've owned it and is fortunately small enough that it doesn't burn my retinas out when I use it. Bosch (green or blue) are at the bottom of my list based on failure rates, along with Milwaukee on the completely unscientific basis that I might be prepared to be seen using tools of any colour (even bright pink) but I draw the line at looking like I'm holding a Tonka Toy when I'm exercising my Manly-man skills.
On hand-held power tools:
Makita is generally highly rated by all contractors and tradespeople, along with Hilti and Festool.
Baier, Flex, Duss and Elu were good names here too, but Elu is Blarrgh&Ducker now. I think I am missing one, but can't get to it. All the others were somewhat tainted by their DIY product lines.
When I did need some power tools, I followed the sum of the professional recommendations and bought FEIN. They have a reputation of being suitable for industrial use and good service.
I have a drill, a cordless screwdriver and an angle grinder from them. For the angle grinder, I was looking first at a original 'Flex', but my toolmonger showed me the then new 115mm Fein with keyless collet and I was sold on it. They served me well and still do. Of course, I will never use that drill on masonry or stone, because the abrasive dust will kill any drill. Got a nice keyless chuck on it from Albrecht (was told to skip Roehm for it - in the US it would be Jacobs maybe). For the mounting and fixing stuff, I use a AEG Pneumatic 2000, as any percussive drill which is not pneumatic should be considered a toy and my frequency of use did not justify a Hilti.