you don't get bethesda games at all, ...their games aren't about the story
That's a rather blunt way of putting it, isn't it? Just because the main quest doesn't cover like 70% of the game doesn't mean Bethesda wrote the story just as a filler.
Fallout 3's story is one of the biggest parts of the game and its events play a great role in shaping the general game world, the largest ones being Enclave and distributing Aqua Pura. It's just that the main quest is very open, with few scripted encounters.
I've always played Fallout 3 for the story, that's for sure. Exploration is just nice extra that in its awesomeness keeps you busy for tens of hours*
*Playing New Vegas, I completed the story and visited 85% of locations in some 35 hours. But today, I visited Mason District for the second and Franklin Metro Utility (y'know, Burnmaster) for the first time in my Fallout 3 experience, with over 1,000 hours played through all characters.