They killed their client and userbase / potential future userbase by not adopting a mobile app sooner, and migrating from Flash sooner. It's insanely telling that they make you install a custom client on your desktop as an alternative.
It's safe to say, Habbo is insanely dead compared to the zillion times we said it, I think this time, it is dead in spirit from what we knew:
A game that had a client that you could just load easily, and could do so much on. Now its a convoluted mess, and I'm frankly surprised they havent fixed the chaos that is their modern client yet.
I mean, if only one guys really working on anything, that is telling as well. I'm not going to count Quackster as someone else working on something, because it is implied Quacksters always messing with Habbo retro servers. Shoutout to all the old farts who still lurk.