Not to encourage anyone to stick with poor acoustics, but a quick scan of youtube vids will show many popular producers making beats in less than ideal conditions.
Example 1
^Not ideal by any means. Big glass windows, monitors in corners, and the room seems odd shaped. Not to mention there is no visable room treatment.
Room reflections seem audible on the video.
Example 2
No visible bass traps, and only some sparse foam for room reflections that you can hear on the video.
Example 3 (the other end of the spectrum)
Alchemist has Traps everywhere on the walls, and corners, and you don't hear the refections in the video like you do the other 2.
This is a pretty ideal room by the looks of it.
Now the 1rst 2 are probably tracking out for mixing engineers in proper rooms, but if they are like most beat makers they do a little sound design on their beats during the whole process.
They seem to get by just fine.
For the record I stand on the side that says room treatment is important.
I was just pointing out some obvious examples of success in crap acoustics to stirr the pot a little.