It's obviously done. Apple wouldn't spend that huge amount of R&D on the transition just to keep using intel. The words of "other intel macs to come" are just lip service. Remember during the powerPC to intel transition, Jobs said the same thing about "other PPC macs yet to come," they never did.Much as I would totally be okay with another Intel 16" MacBook Pro, I have a feeling we're done seeing new Intel Mac releases.
And just because intel announced this, doesn't mean they can actually ship it in volume. Second half of 2021 is a huge range, and can mean practically the end of 2021. Apple's problem with intel is intel's inability to meet their own roadmap schedule, and delays over delays.