professional games require a team of dedicated, inspired professionals.
games like Half life2, doom 3 had more that 100+ people working behind that scenes.
actually, there is a trade off in either time and manpower.either u can make a game in 10yrs yourself, or have a team to make it in a year.
however, to reach that level, u will have to program many smaller games, which can be fun neverthless.
for eg, Currently I am programming a game called HollyWood/Bollywood on my PC.I used to play it all the time in school and it was famous too with classmates.
I remade it simply because I wanted to refresh my coding principles, it took me about 2 hrs to code the game, and I am really enjoying it at the moment.