Pretty much all of that money comes from selling stuff they are only able to sell because of previous government R&D.

For example, without the government leaning heavily on integrated circuits in the 60s, would Microsoft and Google even exist today?

...in late stage development which is MUCH less risky. Super risky early stage tech development mostly happens in the public sector at taxpayer expense through government agencies like DARPA.

A lot of things are easier when it happens with other people's money. A lot of those projects didn't necessarily have the expectation to make/turn a profit.