It really depends on your definition of a "small playerbase" here. I mean, the matchmaking mechanism can also be a problem even for the big names in the industry (LoL, the Clash of Clan series, to name a few here) that have more than 1 mil active playerbase currently. It's no wonder this problem has been the pain in the patootie for APB:R.
It is indeed tragic to see such a game that is full of potential to be fallen like that over the years.
Since the joining of this forum in 2012, we can see the same set of problems have been looped over and over again (Hackusation, playerbase toxicity, threat settings, engine upgrade, unbalancing weapon settings, anti-cheating system, G1 unresponsive attitude...)
People come and go, and yet San Paro stays pretty much the same...