People in tech, why haven't you started a business / company?

There are people who have agencies in other domains. There's also people who work on youtube as a side gig. Why don't more people in tech follow this? Create a freelancing gig, or a small business or maybe trying youtube? Why are most of us hardcore to corporates lives and TC and LC and don't pursue these avenues to high rewards? It's even bad when you go to office.