Ease of installation/use, I think, is the main big one, and one of the biggest obstacles.
People who want to give self-hosting a try aren’t going to be particularly fond of having to jump through a whole bunch of different configs, and manually set everything up.
They want something that they can just set up and go, without having to deal with server hosting, services, and all of that. Something you can just run on your computer, leave it be, and use it with relatively little fuss.
Second to that, would definitely be a case of better documentation/screenshots. A lot of self-hosted things, like Lemmy, didn’t provide much documentation of what the actual user side of it does, only what you need to do to set it up, which isn’t going to make me want to use the software, if I have no idea what it’s supposed to do, and how it compares to other things that do the same.
At the same time, we see a lot that rather than being the emotionless purely logic-driven creatures that they claim to be, Vulcans are still emotional, often making emotional decisions by pretending that it would be more logical to do one thing than another.
Sarek still wound up with Amanda, and cared for her, even if he went with the emotionless mask.
Although by that logic, even if Spock was emotionless, he just had to reach a point where words were no longer sufficient in conveying the meaning that he wished, and as such, he may still have sung a solo.