But the OP is talking about running dozens of servers, not hundreds or thousands. My own modest apps have held up to the traffic from being #1 on reddit and not fallen over, never been null routed or nerfed by DO, and served hundreds of millions of requests and hundreds of TBs of data. I have nothing but good things to say about DO.
I have no experience running apps at the "millions of requests a second" scale, and I'm willing to accept DO might be a bad choice at that level. But what percentage of apps will ever reach that scale?