PC User goes from 386 to Pentium PC and Lotus III or SF2 improves automatically with higher sample rate for sound/smoother scrolling/faster 3D/smoother gameplay. Cost of upgrade is worth it for serious and gaming software.
AFAIK upgrading a 386 to pentium was not a simple drop in replacement of the CPU. Indeed all the 386 PC's I'd seen-mainly HP- had the CPU soldered to the MB. So I have doubts as to the cost of this upgrade being a cheap one as you imply. Pentium PC's were $3000 plus at the time. A lot of money, but PC users did pay it.
Amiga User buys Blizzard 040 card for same £500. Lotus III is still ropey as hell compared to Lotus II game engine and SF2 is still the 5th worst conversion of the arcade in the world.
Lotus 3 ran fine on my Apollo 68040. Blizzard 040's were RC units-recycled CPU's and I don't recall them being 500 pounds. The 1260 boards were about 500 pounds . You wouldn't buy a 68060 to run Lotus or Streetfighter to get a better frame rate. You'd buy it to run a lot of serious apps.
And this is if the games even work with an 040 (a big issue for OCS/ECS games actually). I wouldn't buy an 030 EVER because the 030 is a waste of time and does bugger all an 020 can't do as far as games coding is concerned and MIPS integer type CPU grunt.
A 40/50 mhz 68030 is significantly quicker than a 68020, and AFAIR lets you use more RAM. And the MMU did come in handy for emulation, and virtual memory (gigamem).
I had no interest in ray tracing on Amiga ever so FPU was waste of time and MMU isn't used by KS/WB, and if I did it would be on Lightwave PC on a super fast pentium x PC etc which was cheaper than PPC based A4000s anyway.
OK so a faster CPU wasn't for you. (BTW Lightwave for Amiga never got a PPC version, so comparing the price of a ppc board to run software that didn't exist doesn't make sense.)
Maybe now you understand why people didn't want to blow money on hardware costing more than their A1200 purchased new which would be worth a fraction of its cost as soon as they broke the seal on the packaging. (unless you waited 20 years later and sell it on ebay today in 2010 for a small profit
)
Amiga hardware did not depreciate anywhere near as quickly as PC hardware. The hardware always had better re-sale than a PC. I upgraded to a Cobra 40 mhz 68030 for $299, used it for a 2 years, sold it for $250, then bought an Apollo 68040 for about $400. Later added a CDROM, multiscan monitor. And with each upgrade there was an immediate boost in performance and amount software that I could run.
What I do know is that the Amiga market was made up some of the biggest tight-arses I've ever met. Buying an A1200? Nah too expensive, rather run the old 1 meg A500 and complain why I can't run Doom. Hard drives? Too expensive, but I'll complain about why all the disk swapping. Monitor? Nah just use the TV. Workbench 3.1? Nah 1.3 is OK.
THERE IS NO WAY THAT YOU WOULD GET THE SAME LONGEVITY FROM A PC FOR THE SAME MONEY. The software ( Windows, games and apps) would force you to upgrade the hardware to the tune of thousands, or you'd need to bin your PC. This concept never caught on in the same way with Amiga users, so all we got was games that were made to run in 512k off two floppy drives.