Unless they have very unusual terms on their funding, it isn't really entirely in their control in the long term. Hopefully they find a way to make their investors whole that doesn't suck for everyone else, but if not, well, I at least appreciate that the editor is truly open source, since at least it offers a contingency plan in the worst cases.
If I'm wrong I'd love to know, but I think that we need to start talking about what funding really implies more honestly. It's traditionally met with unabashed enthusiasm and congratulations, which I totally understand, but it's a mutual exchange, not an award or a grant. I absolutely believe that everyone wants to make good on their promises, but promises made to users are not legally binding, and the track record for upholding those has not been great. Plus, as a user, I want to pay for software, but nothing feels worse than paying, then watching enshittification unfold anyways... When this happens, the investors should send you a nice postcard thanking you for paying back some of their money.
Can $20/mo sustain a text editor company with a massive multimillion dollar valuation? Well, we'll see. Good luck Zed Industries, we're all counting on you.