...and then lament when you have to pay again for v2. Or when the software falls out of maintenance because there's no cash flow.
Or not pay for v2 because you still have v1 and it works. Or pay for v2 because it has some new features you'd like.
Ok, there isn't a perfect way to pay for software. Developers usually pick the one that suits them better and it can change along the years. The constant is that they need money to cover their expenses.
Either way, users lose. One-time purchase means probably less software (and less innovation in the space). Subscriptions means more shitty software and user-hostile business models.
Still, as it is, the expected lifetime of a piece of software is usually much longer than the expected lifetime of a SaaS business. So if something seems like a tool I might frequently use, I'd much prefer to buy it than to rent it - there's a better chance the company will abandon it or die than that the bit rot will set.