i haven't posted in well over two years, the forums still not being updated with the old style it once had before some stuff storm happened (idk when this was, i admittedly was lurking) somewhat supports the op's claim. personally makes the forum feels a bit neglected.
the game itself however isn't exactly dead......yet. i mean it's nothing like how it was back when i started playing ten years ago back in V10 but like most games people get bored of them and play something else much like i did.
i was eleven coming up to twelve when i first played this game, still at school with loads of time on my hands to explore the bedroom or one of those gsf city maps. i remember being excited af for the gsf paradise maps to come out, around 2010 - 2012 playing on gravity cat's gov vs rebels tdm/ctf/rp/thing on paradise like it was ARMA on my stuffty amd radeon x300 1gb 1.8ghz duo core pc was the stuff back then.
now? i'm twenty two, full time job working for my country protecting the realm. i don't have the time for computer games anymore or as often as i used to all those years ago and i miss games such as blockland or battlefield 1942 that used to be really, really populated.
now i'm into my cars.
tl;dr blockland isn't dead yet but who knows, maybe one day the game will be booming with players. you can't just point at a game and say "dead" because clearly the community here is still alive on the forums (for stuffposting primarily).