Except its apples to oranges with that comparison, Metro isn't an open world game, the texturing work can be a lot better simply because there's a lot less to texture. That's regardless of the fact that 2033 looked really good for 2010.
Fallout New Vegas was released in 2010. Just Cause 2 was released in 2010. Red Dead Redemption was released in 2010. Mafia II was released in 2010.
The above games are more fair comparisons between 2010 and 2015 graphical fidelity, they're all open world games. Fallout 4 looks better than all of those games, but most importantly, it looks leaps and bounds better than Fallout 3, which if we all remember, looked like this:
They've improved a lot. Texture and model quality being the big things. But the lighting is better, the view distance looks better, and the animations look better. Not perfect, but better.