@Dronecatcher Very interesting article and I find it ironic that back in 2005 they were complaining about the fast release cycle of OS X that we love to complain about today.
I believe that Tiger actually had the longest "life" of any version of OS X(early 2005 to late 2007) although Snow Leopard was close.
I wasn't around Macs very much at the time, but the first couple of versions were brutal-I think 10.0-10.1-10.2 were on about a 6 month cycle, although OS X(IMO) didn't really become useable until 10.2.
To me, a 2 year cycle is about right-I'm not a fan of the current 1 year cycle.
When you read all of those reviews, what I like are their findings that each new version of OSX runs faster than the previous on exactly the same hardware! Guess those days are over!
I had a write-up a while back about a installing every version of OS X on a 500mhz DP Gigabit Ethernet. The difference is definitely noticeable, although even PB is a step up from OS 9 thanks to full-time use of both processors. Tiger flies on that machine, and optimized Leopard is about as good.
Unfortunately, I have to keep a stack of video cards and memory next to the machine, as I'm constantly reconfiguring it if I want to boot into older versions of OS X. Public Beta and 10.0 are particularly bad.
One other thing I find interesting is that Core Image support is present in all G5 GPUs(as well as most aluminum Powerbooks), but the OS didn't take advantage of it until near the end of their life. I guess that Metal in 10.11 is sort of similar in that the hardware for it has been there for it for all computer for at least three years, and some even further back.