"wanting" tf2 to grow and prosper is different than thinking that it can, which at this point, without developer intervention, it will not. none of the systems in place for proper competitive video games are here. there is no matchmaking (the one we have is a complete farce and even people who have never played a 3rd party league hate it), there are no developer hosted tournaments, weapon balancing and game balancing is done at an absolute snails pace (even compared to csgo which is developed by the same company, albeit a different team)
TF2 is maintained simply out of the same passion b4nny or anyone else has, and passion alone does not keep video games alive. There are 1000's of passion project video games that fail, and ours got this far because it was a passion project by people with money, and now that their money is being used elsewhere, it has become the same as any other. something done for the fun of it.
there are a lot of people that both play and develop games like H1Z1 for instance that are still very passionate about the game included, but ask any of them if the game is dead and none of them are delusional enough to tell you no (unless they're playing in the H1PL in which they are contractually obligated to not say that LOL)