Yeah, supposedly the server I am on is almost always very busy and the most crowded of the listed ones, but when I am on a planet (past Tatooine that is, Alderaan and later), there are 8-20 people.
I'm not one of those people who has to play with others to have fun, but I do like seeing people run around.
I don't think people will come back. I subbed for 2 months about 40 days ago. I won't be subbing again, because what's the point? I'll have finished the class stories on a couple of characters and have no particular desire to repeat the planetary quests, yet won't be able to just do the class quest (without having to do KDY a bazillion times). And there's no class or companion story past 50, so no point in continue to play the characters I did finish on.
And there's not much of a community here. It's not bad, but it's like in most other MMORPGs. You have a lot of small guilds that never seem to recruit, you have a few big ones that aren't particular but are aggravating to be in. Trying to do group content in PUGs usually makes you run into the elitists (see all the complaints about bolstering) which isn't worth the frustration.
You really need to change servers...on ToFN you get at least 30 people on most planets in the evenings (just Corellia and Ilum are dead for some reason), 100+ on daily areas (minus Belsavis and Black Hole obviosuly), they are instanced all the time.
And no, I have been subbing on and off for over 2 years but never stopped playing and never got the feeling it's failing - on the contrary, it's growing in spite of all the doomsayers.