As someone who made the horrifically bad decision of buying a G5 on a discount when the first Intel Macs were rolling out... It's been YEARS since that decision, and I regret it still. I got a G5 in 2008, when My B&W G3 (upgraded first to a faster G3, then a G4 processor) finally died, I needed a quick replacement. I ended up getting a G5 on the cheap, and regretted that decision till 2013, when I finally made a Hackintosh. The economic crash in 2008-09 destroyed my finances, and it was years before I could afford a proper upgrade.
Back then, it went like this...
2005 Announcement
2006 First Intel Macs (before the year's end, all models were either released or announced for release)
2007 Mac OS 10.5 Leopard is released (final OS supporting PPC)
2008 Intel Macs stop sucking - I make the horrible choice of picking up a G5 this year...
2009 Mac OS 10.6 Snow Leopard releases (drops support for booting on PPC hardware)
2010 The point when I felt using a G5 was unbearable... By this time, nearly all software support had ended.
2011 Mac OS 10.7 Lion releases (drops Rosetta, killing PPC backwards compatibility)
2011 PPC hardware is declared "vintage". Most support and parts availability is ended
2013 PPC hardware is declared "obsolete". ALL support and parts availability is ended
My take from this, is that by 2025, if we are still running Hackintoshes by then, the software side of things will leave us hating the experience. Sure, we might be able to get it running on some faster hardware for a little while, but eventually, the kernel patches aren't gonna be compatible with new motherboards and CPUs, we won't be able to run new GPUs, the OS will dead end due to the lack of compatibility not only with software, but with the lack of compatibility with newer GPUs.
I found, with my personal experience of owning a PPC in a post PPC world, was that within 3 years of the announcement, almost NO ONE was developing or updating PPC software. Even in 2008, new software was nonexistent. I could only get the occasional update. Even Firefox's PPC build stopped getting complete updates eventually. By 2010, using a G5 as a daily driver was literally hellish. Browsers had long advanced beyond what the G5 and it's out of date software could comfortably run. The spinning beachball of death probably spent nearly as much time on screen than not.
It was a BAD experience!
I'd say, that 3-4 years after the announcement, and 2-3 after the release of the first hardware was the turning point, where inconvenience began transitioning into it being an obstacle. by 5 years after the announcement, there was nothing saving about trying to run a PPC as a main PC. It was unpleasant. I was out of date, with no new software, and web page design vastly outclassing the outdated browsers I was stuck with. I was stuck using this machine in an unbearable state for three more years, till my finances improved and I built my i7 based Hackintosh.
My take from this, is that if history repeats itself, by 2021, most notebooks and minis will be ARM. Some iMacs might be transitioned as well. The Pro models may or may not. No way to really know what Apple has down the pipeline. They did say a 2 year transition, so I expect all macs, including the Pro models will transition by 2022.
Based on the experience from the PPC → Intel transition, I expect Intel software for Macs to entirely dry up by 2023-24. That's maybe one extra year, thanks to Apple claiming a two year transition, instead of the very rapid one year transition, like last time. We will see nothing newly developed, and will likely only see the most minimal of security updates on bigger software. By 2026, I absolutely expect that nearly the entirety of Intel software updates will have completely dried up. If you're still using Intel hardware by 2026, I expect it to be anywhere from an inconvenience to an outright unpleasant experience. Heck... We might even hit that unbearable state by 2025-26.
Now is probably the last time an Intel based Hackintosh makes any sense. After that, it'll just be diminishing returns for a less than pleasant experience.
RIP Hackintosh, you saved me from mediocre hardware 7 years ago. I'll build one more Hackintosh, and then start transitioning to relying on Windows, maybe Linux.