The title is a link. As far as I know, all the databases you've listed are synchronous, lock based solutions, so a single schema can't be grown to any size. Ours can.
No, a single schema can be grown to any size in all of them.
Well yes, technically. Correct me, but wouldn't locks be bottlenecks when scaling databases? Our solution promises the option of a single global database schema, since increasing the number of concurrent transactions wouldn't hurt performance.