While technically true that the block size cap has a hard limit of 4MB, which would be a block consisting of one transaction with only inputs, a 4MB transaction

While technically true that the block size cap has a hard limit of 4MB, which would be a block consisting of one transaction with only inputs, a 4MB transaction isn't valid for other reasons. So it's not meaningful to talk about a fixed block cap anymore. Perhaps it is better to talk about "typical" block sizes the way you do. What's important is that the 1MB limit is history, unless you have to make legacy transactions for some reason.