AFAIK, the ///+ solved most of the problems with the ///, but it failed so badly in the market I’m still looking for one to buy for a reasonable price (I want to try to make it do 384x560 graphics, arguably possible with its interlaced mode).
There's no way a 6502 machine could have beat Z-80 based CP/M machines for business. Not only did the 6502 lack many addressing modes, but it had hardly any registers so you'd struggle even to emulate addressing modes. There was a "direct page" of just 256 bytes that you hypothetically could use to store variables but fitting that into the memory model of languages like C where locals are stack allocated or should look like they are stack allocated is tough.
It was almost impossible to write compilers for languages like Pascal and FORTRAN for the 6502 without resorting to virtual machine techniques like
The latter was atrociously slow and contributed to the spectacle of professors who thought BASIC was brain-damaged advocating terrible alternatives. Commodore added a 6809 to the PET to make a machine you could program in HLLs.
The Apple II was a wildly popular business machine by any measure. Visicalc was an Apple app.
Everyone knows the 6502 is a lousy compiler target particularly if all you understand about compilers is 'what C expects', or at least they did once that became relevant. Those of us there at the time weren't harping on HLL support, since people weren't writing their apps in a HLL but in asm, even on the Z-80.
The big issue with the 6502 is being unable to pass lots of parameters on the hardware stack, but that's all there is to it - one approach was to create a parameter stack independent - you'd just push the size of the called memory space to the hardware stack, using 3 bytes per call for up to 256 worth of parameters and local variables.
I remember seeing C on CP/M circa 1984, the Z80 had compiled BASICs, multiple Pascal implementations including Turbo Pascal although assembly was common. It was still common by the late 1980s on the 8086 platform.
A lot of Apple IIs, mine included, got Z-80 coprocessors for running CP/M. The Z-80 card was, IIRC, the first Microsoft hardware product. Alongside with the Videx 80-column card, it was the most popular expansion for the Apple II plus computers in Brazil as I grew up.
I ran my II+ in dual-head mode, with a long green phosphor monitor on the Videx and a color TV on the main board output.
