Both are Berthseda Softwork games and share alot of simularities. I don't see why they need to compete at all. They draw from the same well after all.
Fallout was created by Interplay, then, the second Fallout 2 was developed by Black Isle, then, they went bust, and Bethesda bought the game
On topic::
I tried to go to New Vegas at lower levels straight after escaping Goodspring, guess what happened