I think you are right. As long as Apple doesn't feel the need to merge them they probably do figure keep both around and many will buy both. However, if something comes along that compels them to merge the two I think they will cannibalize one for the other.
I've had an iPad since its introduction way back when. I don't disagree with your sentiments as I fully expected Apple to evolve the table computing experience much more quickly than it has. As an Apple developer my (pipe) dream was to see the iPad Pro supplant the Mac for most use cases...
Glad you are enjoying the new Mac Book Air. What we can say about memory management on Apple Silicon is that it is much more efficient than memory management on other platforms, Intel in particular for a number of reasons. First is the processor - memory architecture...