> But if you are well established company in the market, then in most cases "do it yourself" is the best idea. Unless you have the money to call for experts to fix the problem for you.

This requires having distributed system experts on your team or having the money to call them from day one, before you even reach the market and before you are even sure you will have custom needs. If you have the need, the expertize and the time, then surely. But writing a distributed system from scratch should certainly not be the first choice (IMO).