Don't let the lack of players stop you from playing this game. Yes it is true, the community is mostly dead and those who are still here are way better than you are. Play it anyway. I'll explain why, and then I will explain how.
Why should you play SMNC even though it has no population and you will get spanked:
The SuperCrossfire mode came out in spring of 2012 and there is still nothing like it. SuperCrossfire is intense, and will make you incredibly angry, but it is the most satisfying game I have ever player. Don't play SuperCrossfire, PLAY TURBOCROSS. When you see these reviews saying that they can't get into matches, or get into them infrequently, they are talking about SuperCrossfire which requires a full team before the match begins. In a perfect world, we could play that mode, but the world sucks so we have to play TurboCross.
Even though TurboCross is watered down SuperCrossfire, it still has no equivalent. Believe me, if I could find a third-person shooter MOBA with jumping, dodging, grapples, and class-synergy, then I would be playing it instead (assuming that more people played it). Here is the low-down, Uber spent millions on this game and it shows. Unfortunately, they didn't make money from it so it has been abandoned. But again, there just isn't anything like it and what it does is amazing.
The basic idea is that you and your team are supposed to help your bots advance in two lanes in order to take down the shields of enemy turrets and eventually take down the money-ball. There are two lanes, so even though you may be pushing one really hard, you have to worry about how the other is doing. All of the maps are symetrical. Now, a lot of players just don't understand how important it is to kill bots. Killing bots is the most effective method of winning the game. Of course the other team will try to kill you while you do it, and you don't want that to happen. Why don't you want that to happen? because while you are dead, you kill less bots. Kill bots, push your lane, take out their turrets once the shield is down, do the same to the money ball. If you see that the other lane is having the same done to it by the other team, switch lanes and push it back to atleast the middle.
Oh I forgot to explain why this is fun. It's amazing. When you and 1-3 other teammates are pushing a lane together and you make progress even though the other team is trying to kill you, you feel like you are making something happen. This is a different feeling than coming in first in a race or having a high kill-to-death ratio. Pushing a lane is slow and must me sustained. When I die, I worry about how far back my lane is going to get pushed and whether or not we will be able to push it back to where it was. It's different than k/d, it just is.
Other third-person shooters just don't offer this.
How to play with a low population:
Play a Pickup game of Turbocross on the North American server after 5pm EST preferably on the weekend. Yes, I know that this is limiting, but it's what you have to do to play this game that no one else has made yet and is ahead of its time.
It will take maybe 10 minutes to find your first game, but after that you are in rhythm, so most of the players of your last game will show up for the next. You will see the same names on different days, there are not many of us. Be nice because you will see them again. They will not be nice to you, I am sorry. Stay near your team and kill-bots. Stay on one lane until you know the maps. Eventually you should ask someone what the annihilator is. Good luck.
If people knew what this game was like, there would be a lot of people playing it, but it looks like Team Fortress 2 and when it don't play in a similar way, folks think it is a bad game. SMNC has major flaws, but there just isn't anything like it and what it does is valuable.