My question is: why not? I understand that the best way for a two-person team to get a prototype up is by bringing up 3 EC2 machines with PostgreSQL on one, MongoDB on another, and the Rails stack on the third. This is when you have no money; but it seems that even when a company has closed a post-Series A round and has plenty of money, there is still resistance to buying a huge Oracle/Sun box with terabytes of RAM and petabytes of storage on a SAN, and instead there's usually a team of engineers doing life support on a Mongo or Cassandra cluster. It's worth pointing out that three engineers at $100K each is probably the amount one would pay for a few huge boxes.