It's not that it's short so much as it is the way the game does textures. There's the distant & closer texture qualities etc, and as you're running around, it constantly loads/switches them in as you reach certain distance points. Thus you always feel like you can see stuff "drawing in" because the difference between those two sets of texture qualities is so noticeable to the eye. Or something. Maybe I'm wrong on tech specifics but that's the visual effect anyway.
You can mess with the .ini files to increase view distance past the game's natural maximum, and it does help somewhat with some stuff, but you will still notice that pop-in effect as you approach mountains & buildings & whatnot. If you want distant hi-res textures you need "serious" texture mods for those, and if you do that, the performance hit is very noticeable even on hi-end rigs, especially regarding loading times.
Edit: You can use this configuring tool to alter the view distances. Just be careful about altering too many of the graphic settings, the game doesn't always like 'em... http://www.newvegasnexus.com/downloads/file.php?id=40442