So it is essentially a given that Biden will win the popular vote

[Statistical]

1. Yeah the country may have been center right 40 years ago

but the GOP has pushed further and further to the right into crazy land while the population has drifted left.

As you point out if the country really was center right they should consistently and easily will the popular vote. They have only once in 32 years and that Jr's re-election in 2004. Re-election's strong favor the incumbent so not really sure that shows a conservative bent more a re-elect the incumbent bent.

Most of what the right calls radical leftist ideas like a $15 minimum wage, higher taxes on the rich, universal healthcare, taxpayer funded higher education, etc are supported by a wide swath of the electorate. They aren't "leftist" ideas they are centrist ideas.