Sadly, I believe this is a case of survivorship bias.

Rollercoaster Tycoon was also developed by one person. Developers could also be absurdly efficient in the past, see valve and half-life 1 as an example.

It means little to give examples of cases where developers punched above their weight and arguing it was because of reason X they could achieve it in the first place.

How many people failed, was it because of missing tools?

Like before, people will attribute some of their performance to tools, that in reality didn't matter at all.