If sublime text were to end all support today, I would have gotten triple-digit returns on that 75$ investment. Same for most software. Don’t get me wrong, unsupported paid software sucks and open sourcing abandoned projects means I would be more likely to buy something from that person/company again, but on some level a market clearing price takes this risk into account if we’re just talking about consumer applications.

It certainly depends on the software, too. Some things are more fragile than others, for one thing. Perhaps more importantly, some software is harder to migrate away from, e.g. if it has a database, especially some custom file format.