I think at least part of it is that they're tired of having to fix their channel every time Toei gets pissy and takes down all their videos.
My Tumblr. Currently side-by-side liveblogging Digimon Adventure, sub vs dub.That's probably a bit of a lemon squeezer.
It keeps on happening, that would've stopped most people by now.
Rules of the Internet 45. Rule 45 is a lie. Check out my art if you notice.The big issue is that Youtube effectively has a monopoly on online video platforms. TFS used to have a different player on their website but they went under. Other "rivals" like blip.tv and vid.me ended up crashing and burning.With Youtube's Content ID system being total ass, I can see it being disheartening to try and continue to get produce your work on the platform, especially since TFS is in the grey area as far as fair use goes.
We also have to consider that time might lead to them drifting apart and doing their own shit.
One Strip! One Strip!I doubt that. They already have their own channels where they do their own shit, but Team Four Star as a company has only gotten more cemented with time. They've had, what, three different studios so far? They have multiple shows and multiple channels dedicated to all of them doing stuff together representing the company, not themselves. I think Team Four Star as a company is going to be fine for the foreseeable future.
Does HBI 2 K have his laugh logged under Annoying/Noticeable Laugh in the wiki? Because it really deserves it.
An important thing to remember is that they technically don't get any money from DBZA. People can support them through Patreon and other ways, but someone who just watches DBZA and nothing else isn't giving them any money. So how DBZA ending impacts how much money they are getting will be hard to guess till it happens.

What exactly is the issue? I mean, I know Toei doesn't like them doing it, but has the situation gotten worse? If they were to start the Buu Saga is there reason to think they'd have to stop before they'd be done, thus they might call it quits after the Android Saga wraps up so they have a good place to end?