This is a very niche use case. The vast majority of projects have neither the user base to arrive to such numbers, no are they I/O challenged. Most companies are not facebook or google.
Plus if you manage to do 50 write sec on this DB, I don't see how you plan to scale anything with it. You are back to use good old sharding with load balancers.
Plus if you manage to do 50 write sec on this DB, I don't see how you plan to scale anything with it. You are back to use good old sharding with load balancers.