That's not to say that it's impossible to do anything on your own nowadays. I hear that it only took one guy to make Evochron Mercenary (http://www.starwraith.com/evochronmercenary/faq.htm#2) and the game takes roughly 1gb. Now, Star Citizen is supposedly the next big space sim; a big team that has raised over $50 million and creating a game that will probably take over a 100gb to install. Heck it took 20gb just for me to demo the dog-fighting module.

One developer vs a team backed with millions of dollars.

1gb vs 100gb.

It can still happen.