It's amazing to me that so many people make "stuck with Rails" arguments in the enterprise. It's extraordinarily clear to me, having worked in 3 Fortune 250's, that the single, most-attractive-to-management feature of alternative stacks like Java and Javascript is... dun dun dun!... MASSIVE project bloat! Justifying huge teams and years of development time, leading to huge budgets and personal power within the company.

As a single, full-stack guy, I've out-coded entire teams of Java programmers TWICE using Rails. And none of the projects inside even-a-Fortune-size company come anywhere near concerns about "scaling" like we're discussing here.

So my takeaway after decades of doing full-stack development (also with PHP and .NET) is that Rails absolutely murders every other stack for time-to-market or MVP or whatever time-based metric you want to us, and has no effective liability in performance. The only places were are even discussing this kind of scalability is on some of the highest-trafficked web sites in the world, and even then I'd bet real money that the team size and time to develop features are still killing it over other stacks that would "scale" better.