Yes, that seems a reasonable view. But the corollary is that paying money for FSD right now is somewhat of a pointless purchase. On my part, there's no way I'd part with £500, let alone over £5000 for it based on my experience with AP.AFAIK, there's no separation between any of the front end sensing and processing, so any sensing/feature recognition issues in FSD will translate across to TACC and the always on emergency assist features. If something gets fixed for FSD, then it seems very likely that it will also get fixed for the other driver assist functions, if it's a sensing/feature recognition issue. I get the feeling that 99% of the fairly common problems, like phantom braking and random steering corrections are just the car systems being confused about what's being sensed, rather than anything specific to the car dynamic control stuff.
Maybe the new rewrite will be a big improvement. If it is, Tesla have an interesting decision to make - bring its new capabilities to AP but with features removed, or leave AP as is and only use the new software for FSD. The former may convince people like me to pay the upgrade since I can now see that the basics are working, but OTOH, the latter route will put clean blue water between the two which may be a better overall incentive.