When you're paying a subscription you are paying for the maintainer's continued interest in the product over time, which is not to be underestimated. Software rots quickly.
ST2 has been out for over 6 years and ST1 was initially released 11 years ago (based on the wiki). I have to imagine he made really good money. Possibly even so much that he lost interest after hitting a financial goal.
Back in 2017 MS said more than 2.6 million people use VSCode on a monthly basis. That's not downloads, but monthly users. It could maybe be double that by now (who knows).
But if you're talking about millions of active users, I don't think it's unreasonable to think 3-4 million people used Sublime in its life time -- especially before VSCode existed.
If only 1% of users bought it (40,000 sales) at $70 = $2,800,000 dollars in a business where practically all of that is profit. That doesn't even account for the $30 price to upgrade from ST2 to ST3. Even if he only sold half of that amount, that's still crushing it over a 10 year period of time.
I also disagree that you can even compare Sublime to VS Code because one is a text editor and one is an IDE. I don't know a single person that switched just because Sublime wasn't being updated, they switched because VS Code has some really deep integrations and features that are easy to become dependent on.
Alfred has another better option than subscriptions IMO where they release new major versions you have to pay for every couple of years, but you own the previous version in perpetuity.