laptop 7 was a plague, HP Pavilion dv9000 was one of the most famous victims, I am guessing mobile 7 wasnt as popular as 8 series so you didnt hear about it as much.
desktop 7 didnt die en masse afaik, or at least were replaced withe newer gen cards(7 to 8 was a massive leap in performance) fast enough it wasnt noticed.
desktop 8 was a disaster, its quite rare nowadays to find a high end working 8-9-2xx series card, my personal collection is full of dead ones (8800,9800,285), every card died in 2-5 years, all bad GPU. Anecdotally I also have 7600 GS which survived running 24/7 10 years with a voltmod and aggressive 50% OC (400/400 to 600/600 MHz), finally ended up frying ram supply controller. I dont even recall Collectors complaining about 7 series.