Honestly the issue with expansion is not so much that minecraft is running out of steam, its a matter of simply that minecraft no longer has a free iteration. It costs money, 27 usd to be exact and that's quite a bit of money.
With the relevance of steam ever growing and quality games costing pennies on the dollar it is not hard to understand why we do not get many new players.
Simply people picked up the game during its cheap big bang and the dust went everywhere, now years later its settling down into galaxies and many people do not want to make the arduous journey from one to another because it may not have what they find they need to support their interest.
Back to the issue at hand of what really works for a minecraft server group. That is, and has usually been ~ attention grabbing and attention whoring.
That is referring to ads on their forums to generate revenue, then pushing that revenue into hiring programmers to create batshit crazy content, then into paying for adspace on relevant minecraft related places, rinse and repeat.
Not even going to delve into the pay-to-receive-in-game-bullshit-server-places.
Now you might argue this group has never been pay to win or ad filled. Well lets cut that childish ideology out right now. No I'm not saying lets become pay to play. However I am saying its time to wake up and become adults about this. Nearly any site that doesn't have sort of crypto currency or pay benefit survives on its ad revenue, even going as far as to reward you for watching ads or having ads along side the pay to win. Its applause worthy that we have lived this long on donations alone.
However, truthfully, over the years, and this matters quite a bit comparatively. How many donators have their been over the x+ years of this groups life after becoming blocktopia. Less then 100. 150, 200? The numbers on rough estimates are appalling. Given there are twelve months in the year and there was a year payed for by a single person almost immediately, lets exclude that into about 4 years.
That's 48 months, 150 each month, hell wasn't it 200 at one point? swear it was and I filled it like the literal minute it opened and got people upset, my memories fucked, anyways. With it being 150 a month the generous thing to say that a donation system would be succeeding is if multiple members donated anywhere from 5-10 usd. Estimating that anywhere from 15-30 different individuals a month, give or take a few repeats here and there.
Doing the math we should have anywhere from 400-800 unique donators of the lifespan of this system excluding the yearlong dominance for the system to be credited a success.
Do not look me in the face and tell me having 400-800 unique donators over the lifespan of this community is absurd, look at the poster above me kuvir, his membership number is 6108, doing the average that means we have gotten roughly 1000 members per year and having 10 percent donate ten dollars is like condensation on the side of a water bottle. The only argument you can have is that the community is fairly towards the 'kiddie-pool' end, however most members are of respectable job aged.
I would love to see where the community can go however the ideal that we would have to focus on games that are only free to play is relatively awful. We are not going to get another two or three years out of these free to play games, let alone another five years before the content winds down.
Its the proverbial 'where do we go from here'
Case in example were the garrys mod server boomed then busted, again with infection.
One of the main downfalls of blocktopia currently is the tight-assed-ness. Its a valuable commodity, but a huge deterrent to growth. What makes plants grow big and strong? Well m'boy that would be grade a quality shit. Now I'm not talking the harmful shit, I'm talking shit that stinks just the same and you really do not want to have your hands on it or even deal with it, but you want those plants big and beautiful with lots o fruit right? Well then your gonna have ta gets yer hands covered in it.
This isn't saying 'lighten up' this is saying there is just some shit you have to put up with.