I’m sure what he said was that apple had a two year plan to switch from Intel to apple silicon across their range. He also said that Intel macs would be supported for years to come. I certainly don’t remember him saying that developers had two years to move to apple silicon. People are still buying Intel based 27” iMacs and Mac Pros!
Not sure what selling intel macs has to do with rosetta. I’m thinking it has another another two years at most. Few will waste time updating for m1 as long as rosetta is around. The sooner the cord is cut the better.
The tricky part is what you can run today may not be happening in a year or two. All those intel mac apps and games go poof. The majority of mac buyers are probably oblivious to this.