That is what happened to me. Two 2008 iMacs needed to be replaced in the house. I have been waiting for a new mini to do this, for a while now - But nothing!!!
I replaced one(son's) with a 2013 iMac where I got a great deal from someone at work. And for the other(mine), I got a PC that is only Windows/Linux. I've transitioned some items over there - like pictures and videos, as well as photo processing software. The world of gaming has also opened up to me. This thing curb stomps a $4k+ Mac Pro, for less than $1400. It's not small, but then again, I was able to actually CHOOSE what I wanted in The machine, versus being dictated to.
I still have my 2012 15" cMBP, which is mad upgraded. so while I've not left, I'm barely hanging on these days.
I've ended up going the route of tinkering with the hackintosh idea.
I haven't thrown any real money into the experiment yet. More just practicing on some old hardware I have around.
So, just to get my feet wet, I've dug out an old Dell Optiplex 745 SFF (small form factor) with a 2.13 GHz Core2Duo. I've thrown a 2 terabyte hard drive and 6 gigs of RAM into it. And thrown both Windows 10 Pro and El Capitan onto it.
And admittedly setting it up initially was a pain. But... after a bit of practice (retrying different methods, it's actually gotten fairly simple).
Really the biggest challenge is getting the boot loader to permit swapping between Windows 10 and El Capitan on the same hard drive when I'm not using a UEFI system. I have a GPT / MBR hybrid partitioning setup which is cumbersome. But would be unnecessary on modern hardware.
If I threw modern hardware at the experiment, it would be easier.
But.... I do have El Capitan and Windows 10 both on the machine. Each has 1 terabyte of the hard drive. And I must say, El Capitan runs great on it.
By "feel" it is snappier than the 2012 MacBook Pro i7 machines I've worked on for other people.
And it is very stable.
While I would say it's definitely not as easy as installing OS X on a real Mac, it is easier than installing El Capitan on a 2006 Mac Pro.
Now, if you wanted to experiment with the idea, I would recommend not doing what I did. Instead install OS X and Windows on separate hard drives. I only did it on the same drive due to the machine only having one drive bay (and I didn't want external drives - though external USB installs did prove to work just fine).
The hackintosh option definitely is viable. Just takes a little patience.
I still prefer real Macs. But after tinkering with the experiment, I do see other options if Apple continues to fail to deliver a machine that is both a great performer and competitively priced.