We need to talk about how difficult it is to monetize browser extensions. Most of these problems occur when a reputable extension gets sold to a less reputable owner, frequently for a relatively small amount of money (4-5 figures). Even very popular extensions have a hard time monetizing. Unfortunately, Chrome has recently made the situation worse by deprecating Chrome Web Store payments, and Firefox eliminated their paid extension store several years ago.

If the only way to monetize an extension is to exploit its users for data, this kind of thing is going to keep happening. It's perfectly understandable how someone who is doing a lot of work for no pay will eventually get tired of it or have other priorities in life, which is what happened in this case. Perhaps we all need to stop taking it for granted that browser extensions ought to be free? Or maybe the browser vendors themselves can find ways of financially supporting extension authors. I feel that money is essential to both the problem and the solution.

Of course, paid upfront software gets sold to new owners too. But if the software is paid upfront, the expectation is that the new owner will perhaps do a better job of maintaining and marketing the software, and that's why the new owner buys it. When the software is paid, the new owner has an opportunity to make money legitimately, without secretly exploiting the existing user base.