And if they don’t keep updating it, it will stop working and the buy it for life idea commits the dev to maintenance that isn’t paid for either upfront or through subscription.
There are folks who make and give away a lot but some learn their lesson quickly and find ways to get people to put a reasonable amount of recurring payment into the app to make it even remotely sustainable beyond a hobby.
FWIW, AI may make this cost so much lower that this kind of thing can make sense now. Something to consider, I suppose.