I think it's unfair. "Modern" is in no way equivalent to what the thread is really asking, which is what could you do if you built a new database today with all of the knowledge but none of the existing commitments of a large mainstream database.
It’s fair because these databases made trade offs for older ideas presumably for good reasons. The question isn’t what could the have done differently up to now, but rather what new ideas might designers have included if they existed back then.
Modern software development practices and knowledge are orthogonal to feature set / compatibility guarantees. The title asks about the former and the text asks about the latter, and I don't agree it's correct to conflate the two
Although most of the responses have been for ideas that did exist back then, but have significant trade-offs, both then and now. They're mostly just different approaches to db, not something fundamentally "modern".
