After reading the other answers...
Don't forget about the medical industry. Especially the billion dollar one called Telemedicine. Folks 60+ and older are still using Vista, can't leave their homes and need to have a video conference. This is why, whether current browsers love it or not, Flash is a necessity.
Also, X-Ray software that hasn't been updated for over a decade - and is needed to run antiquated devices - are running on Windows 98 PCs.
Unfortunately, we'll all be there. Running a quad-core i7 4ghz CPU, with 32 gigs of RAM and a 2 TB SSD in 20 years, may not allow you to update to the new version of Chrome - with Super-Duper's Vidirama GoWoah 2.6 - until the hardware is upgraded too. And, if at that point, you're living on social security... good luck with that one.
So, accessibility and backwards-compatibility is much more important than people give them credit for.
Also, don't forget about vendor prefixes. If I were to attempt predicting a "trend gone hog wild" - it will be the requirement of something like Modernizr to become native in the future, because Moore's law is basically explaining to us why we update 36 apps on our phones and wake up the next morning to update 48. Everyone loves to go their own route, without paying attention to how much of an incompatibility issue they're creating within the standards that will eventually evolve even more.
However, I'm a fan of the horse and buggy... and don't mind creating artwork on paper as well as socializing with my neighbors over a barbecue.