I agree, and I'm not criticising the choices that Mark Zuckerberg made at the time. But we are no longer facing the same situation he did. We do now have high productivity, high performance language runtimes. And scaling up has become much cheaper (relative to the number of users you can serve).

That's why I think it can't hurt to remind people of the great lengths to which Facebook had to go in order to deal with the limitations of their chosen platform.