Well...200k in 1975 $'s. And MOS was a startup, basically. So not a trivial amount. But yeah, a big part of the initial pitch was "you can use your same hardware design but replace the $300 CPU with our $25 CPU".
That's seriously ambitious (tips hat). There were a number of folks that came up with dual processor designs back in those days playing on the observation that most 8-bitters (and many 16- and 32-bitters) could never utilize more than 50% of the available memory bandwidth. There's an NS32000 application note somewhere that describes such a design, and NS had datasheets for an NS32132 that was an NS32032 with added some support for such a system. I dunno if the NS32132 ever shipped, however.
There was also an argument that the 6501 was built as a sacrificial lamb so that when Motorola inevitably sued them, they would be able to keep the 6502 out of the case.
The 6501 and 6502 were developed simultaneously and the 6502 was released a month later (Aug 1975 vs Sept 1975). Both well before the lawsuit began, yet alone concluded.
