I've been a Mac user for years, and I've repaired hundreds of different Macs, from the early II series to the latest 2015 and 2016 model MacBook Pros, iMacs (and other Apple hardware to boot!), and there is almost never a hardware situation where I've thrown in the towel and told someone to ditch their Mac.
The 2011 MacBook Pro has, for almost a decade, been the exception to that rule. There was a major flaw in the AMD Radeon GPUs included with that model year's logic board which seemed to cause GPU failure either due to overheating, internal chip problems, BGA solder joints getting broken, or a combination of the above. The problem was so rampant, Apple was forced to set up a free repair program for affected MacBook Pros—though the 2011 model has since been dropped from that program. I've handled three 2011 MacBook Pros (none of them my own—I had an Air back then), and all three of them were scrapped because of the GPU issue.