You see this as somehow distasteful, or as 'begging', which just seems to me to be sour grapes that they're doing what you seem to be unable to. I don't mean that as intentionally mean, but again, this is the 'business model' that's worked for them for years, and apparently the same business model that hasn't worked for you.

Could they be doing it better? Sure. There's always room for improvement, but they deliver a quality product. In return for that, they occasionally solicit for donations. It's quite possible that they do all the things you've suggested. It's quite possible that they ordinarily run at a surplus, but haven't been raising actively, or haven't been receiving donations. It's possible that they've already sent an email to their user base and gotten a less-than-ideal response.

They're moving data centers, so it's possible that they ate up some of that surplus in the migration effort, which tends to get costly.

Either way, I don't personally see this as begging, and they've already hit their goal, which should help to reinforce how valuable the service is. That they aren't homeless, in debt or trying to file for bankruptcy shouldn't count against them.