Rosetta 1 was licenced third party technology back when the company wasn't exactly rolling in money.
https:/www.wikipedia.org/wiki/QuickTransit
If you have to pay the licensing fee again every time you want to release a new version of the OS, you've got a fiscal incentive to sunset Rosetta early.
Rosetta 2 was developed in-house.
Apple owns it, so there is no fiscal reason to sunset it early.
Rosetta 1 wasn't really useful for much because PowerPC was a dead platform by the time Apple switched off of it. Rosetta 2 is used for much more than just compatibility with old macOS apps.
https:/www.wikipedia.org/wiki/QuickTransit
If you have to pay the licensing fee again every time you want to release a new version of the OS, you've got a fiscal incentive to sunset Rosetta early.
Rosetta 2 was developed in-house.
Apple owns it, so there is no fiscal reason to sunset it early.