I would have to agree with OP.
Dave Haynie..... "we had in West Chester chip designers every bit as good as those in Los Gatos"
If this is the case why was there zero improvement in useful aspects of OCS chipset in 1985-1991. As far as I can see all they added was 1mb Chip ram then 2mb (this can be useful yes especially 1mb) but hey Shadow of the Beast runs in 512kb doesn't it?
Other than that we got some crazy 4 colour screen modes and double PAL etc. I see no evidence of any attempt to improve parallax scrolling rather than the crippled 2x 8 colour dual playfield mode or 64 usable colours on screen or even a speeded up EHB mode to make it usable.
And also if this is true why was Commodore's answer to Atari ST the C128? Hardly Amiga 1000 chipset levels of genius? Let's face it if Commodore or Atari had not got hold of Amiga chipset then of the two machines which would people have bought for 400 bucks? Exactly! +4 was nothing special, the C128 made hardly any improvements to 1982 C64 as a games machine hell it couldn't even run VIC-II @ 2mhz in 128 mode and 2mhz compatible VDC had no sprites and no extra colours after 4 years etc.
Amiga was what stopped C= going bust after JT left, they were clueless beyond belief and projects that should have been canned made it into production.
To me it looks like the chip designers left at Commodore would have to reverse engineer the stuff, and they didn't get very far. And way before VGA 386/486 PC there were a few machines with 128 or 256 colours on screen around the time of A2000/500 so the writing was on the wall and we all know this is where we had to be (more than 32 colours on screen and better parallax) to compete with future machines.
The original designers came up with the following chipsets....
Ranger
Lynx
3DO
Which apart from VIC-II and SID Commodore engineers never really reached that level of technical superiority ever again really.
+4/C16 nothing special
C128 chipset less capable than similarly priced Atari ST with no custom chipset.