As a cat owner, you get used to it.

If there was demand for more high performance 68k processors, presumably Motorola would have made more. But by the time of the 68060 customers for high end 68k had either already moved onto various RISC architectures (Mac, UNIX workstations) or were dead / dying (ST, Amiga).

A related question would be if Motorola could pull off what Intel did with x86, and drag the architecture to be competitive with RISC. Part of Intel's trick was that x86 isn't the most CISCy of chips, so it was easy to implement a processor that takes a "RISCy subset" of instructions and translate them into one or two µops. 68k is perhaps more on the VAX side of things, so whether they'd be able to pull off the same trick is a bit unclear. Clearly we need to check the parallel universes where IBM chose the 68008 for Chess instead of the 8088...

Motorola wanted to replace the 68000 series with their RISC design, the 88000, so it was probably always going to end there. Their customers were also all in full RISC hype fever and were looking for RISC chips to move to.

In Apple's search for a RISC chip, didn't want to be stuck being single-sourced again so they had IBM and Motorola work together to launch PowerPC instead, so Motorola gave up on the 88k.

We did, sort of: https://en.wikipedia.org/wiki/NXP_ColdFire

Coldfire V4/V5 are significantly faster than 060.

someone did https://tinkerdifferent.com/threads/pistorm-on-the-macintosh...

personally I think it's a bit too close to just emulating the whole thing

Vampire is not really a 68k, it's an FPGA based system. A kind of fantasy could-have-been system.

There's at least one implementation, a Mac Plus:

https://www.bigmessowires.com/plus-too/

68060 has a reduced integer and floating point instruction set ( Motorola cut down some of the lesser used instructions in order to keep the die size under control. However, to remedy this they made available an ISP (Integer Support package) and FPSP (Floating point support package))

Bus error stack frames have been changed significantly

(per the bulletin board discussion linked below)

https://www.cpu-world.com/CPUs/68060/index.html:

“Supervisor mode of the Motorola 68060 CPU differs from the 68040 due to changes in exception processing. User mode of the Motorola 68060 is object-compatible with MC68040, assuming that the CPU uses special software to simulate a few instructions that were present in 68040 CPU and are missing in MC68060.”

Big picture: Motorola's 68K architecture was a case study in Death by Feature Creep.

Short-term: The 68K was loved by assembly language programmers - a big thing, in the 80's. And it felt and sounded so cool for Motorola to add even more great features to each generation of the architecture.

Long-term: If you want your microprocessor architecture to stay a thing in higher-performance desktop/server use (vs. toaster ovens & thermostats & such) - then you need to have a few Senior Implementation Engineers looking a decade or so ahead, and saying "NO" to cool features that could turn into implementation hell.

The 68060 was where the long-term issues really caught up with the 68K architecture, and it hit the brick wall / grave stone. Which is why Motorola pretty much dumped their 68K for IBM's Power architecture, in the PowerPC.

I’m far from an expert, but it seems pretty common for new CPUs to be compatible with old ones at the application level, but not fully compatible with OSes. It seems like there’s a (reasonable, I’d say) assumption that vendors are willing to update the OS when they ship new hardware. Of course, this makes it hard to upgrade the CPU in a machine that hasn’t been supported for decades.

I’ve got a 68060 RC (MMU, no FPU) in my Amiga 1200 and it seems to work alright. The full 68060 is insanely expensive these days though, you could get a decent Ryzen for a lot less money.