> Databases have always had FLOSS alternatives.

Relational databases have had [technically] open-source alternatives from the beginning, you're right. But they were also always playing catch-up to commercial databases. Oracle supported SQL long before Ingres, making them the lead product at the very beginning, and their services and support (and superior marketing power) kept them at the forefront.

Corporate or military investment is usually what drives cutting edge technology, which is adopted by necessity.

> anybody on here want to work on some kind of innovative enterprise database startup? (I don't have any ideas, I just want to work on one because I see a lot of potential)

Find out what a huge corporate product is lacking, make that, and then get them to buy you.