Ask HN: Efficiency vs. efficacy of tech stacks

Tech stacks are endlessly fascinating for HN readers. I think its because we suspect that part of the reason a startup is so successful is because it uses the right tools.

Many of the tech stacks one finds are massive for 1000 enterprise companies:

http://techstacks.io/

I consider these to be effective. They cost a lost, but they keep the thing running.

On the other end of the spectrum there are probably tech stacks that are used by a single founder to get their side app up and running.

These are likely to be: rails, django, etc.

Is there any study, clue, anecdotes about efficient stacks?

I am looking for stacks where:

1. A single founder or two

2. Build out a massive product

3. And carry it on for as long as possible before having to scale up.

My suspicion is that we may find these founders all use similar stacks.