If it was planned, Rosetta 2 would have never existed in the first place. It would have been a qemu fork haphazardly crammed into Xcode.
There was no "planning" here. Here's how I imagine it went: a developer whined about tech debt, management seized an opportunity to generate revenue, neither party considered, yknow, humans, and now we're here.
For day to day tasks there is no difference.
I think "M series chips are no better than ten year old Intel chips" is a take that would be somewhat difficult to sustain, given the data.
Btw she can downgrade to Sequoia from Tahoe.