Rosetta-a-like is absolutely necessary
Remind me, just how successful was WindowsRT?
The operating system isn't the major hurdle when changing CPU/GPU architecture, it's the applications.
If none of your existing applications will work, why would you buy the new Mac?
Why would a software house spend the resources making it work at all on the new platform, unless their customers are going to buy it again?
Software like Adobe Creative Cloud is fine of course, because their customers are already paying monthly, but anything you already bought will probably have to be bought again.