Sorry for the delay in replying- life intervened.
It’s an interesting debate certainly and you’re right that the definition of a ‘classic album’ changes over time. What I do think is that such albums almost always need a certain seriousness of purpose - that’s certainly present in most of those you mention (definitely in people like Kendrick, Solange, Frank Ocean etc).
A ‘pop’ album with four or five massive singles and some filler is probably far more financially lucrative but has a different set of aims. I’m not saying either one or the other is more worthy or valid, but I think they are still different.