It's a very old engine, that much is for sure. But lots of players would be awesome. Advertising nonetheless doesn't have to be by profit, most people seem to have shown up from stuff like CNC-Net, Moddb, Youtube, etc. I myself found out about APB from Moddb while searching for RA2 mods. There's certainly outlets available, and those outlets probably should be taken sooner rather than later. Games like this need more community, and the lack of players is kind of self-perpetuating; thankfully if we get more players again it may stabilize since this whole genre is fairly specific and the price tag is quite reasonable, with no hidden strings or high hardware requirements.
As for the netcode, APB was, until Delta, paced differently than for instance RenX. It was more slowed, strategic, maybe just how I'm remembering it, and what set it apart in my mind was the more tactic/strategy influence. That's what always separated Renegade from CS and other fps games. Competitive was more "clever", although Delta's pacing seems far faster.