1) Not necessarily, as the thermals would presumably be different, the use-case is different (not everyone wants or needs a laptop; expandability of the Pro, etc.) and Max =/= Ultra, especially if you're crunching local inference.

2) Even if there was some cannibalisation, does that matter? Unless we assume Apple is running a higher profit margin on Studio/Pro machines (unlikely, since laptops are more expensive than the equivalent Mini/Studio) they're still making roughly the same money at the end of the day. And for the higher end (i.e. workloads needing the Ultra and/or >256GB RAM) there's still no competition.

3) I'd not be surprised (RAM shortages aside) to see the RAM options on the Ultra increase before long, maintaining the differentiation, just at a higher level.

Basically, Apple stumbled into relevance as (amazingly) the most cost-effective option for local inference. Having found themselves in this position, it would be a huge fail to not lean further into this. They seem to be doing this to an extent by optimising chips for e.g. prompt processing, but increasing the RAM is needed too.