The 68000 really took over from the 6502, even though it was completely incompatible. There is a 16-bit 6502, called the 65816, from WDC. They are still in production today and were used in some very high volume applications, like the SuperNES game console, but only really in the Apple IIgs personal computer. By the time the 65816 came out the 68000 was well established both in workstations and in the Atari ST, Commodore Amiga, and the Macintosh. The 68000 family had a long life and competed quite well against x86 for a while.
The 68000 really fascinates me, because it has an interesting legacy: the m68k ISA was heavily inspired by the DEC PDP-11 (the classic Unix architecture), and the assembly language was almost identical.
If a few things went differently, the modern computer industry could've been dominated by a descendent of the PDP-11...
Instead, however, we got x86, which is the worst of all possible worlds. People like to shit on x86 for being CISC instead of RISC, but the truth is that a good CISC architecture has lots of things (e.g. orthogonality) that can make up for not being RISC, and x86 is just a really poor example of CISC. The ultimate CISC ISA was VAX, but PDP-11 and m68k came pretty damn close, and it's a real shame that they got crushed under the x86 juggernaut.
x86 works really well as an ISA in the modern micro-op world. The instruction stream acts as a primitive kind of compression - common programs are more concise than they would be under either a fully orthogonal or a pure RISC approach.
