If you ask here why they only have 4 developers and whether they shouldn't hire more people, you get no answer.
Twitter had 8 employees in 2008:
https://www.statista.com/statistics/272140/employees-of-twitter/So maybe half of them were developers. How many of them do you need to make a good product? And what will happen if they hire 100 more to satisfy you, and they are all crappy programmers? it is really hard to find good ones.