It's a detail that doesn't always come up in these threads but it's worth remembering how belligerently 8-bit a 6502 is. Not only are there next to no general-purpose registers but they're 8 bit and there are no pretend-two-registers-are-one-16-bit-register instructions at all. You can't put an address in a register. Compared to even other popular 8 bit CPUs of the time, that's a bit metal.
Combine that with the Apple I and II, and the 6502 was a major player, and the 6800 didn't have any massively compelling benefits.
The 6809 did have benefits over the 6502, and did get some design wins, including Commodore's SuperPET (which bizarrely had both a 6809 and a 6502), but I think the 6809 was too late - on the low end cheap machines like the VIC-20 and then C64 completely trounced the 6809 based machines, and so it just didn't get enough mindshare, and just a few years later it was effectively too late for it to get any traction in the home computer market.
I have not written much 6800 code, but have read a fair bit. Had it been more available to me, I would definitely enjoyed it
The 6809 is the Cadillac of 8 bitters. That is what makes it fun. One can pack a ton of features into small spaces and doing reentrant, relocatable code is very well supported.
Stack abuse gets one a really fast memory to memory move too.
And doing something useful with 56 instructions, 8-bits at a time, is like solving a puzzle.