You own a license, instead of paying for a license in perpetuity.

When the software requires continuous updates and a server component and storage and things, this doesn't make any sense.

There’s a ceiling, a point you can never pass, with a subscription model due to churn. There isn’t a ceiling with one-off purchases.

Subscription's exchange a higher ceiling for a higher floor, which makes running a business much easier.

Isn't the one-off ceiling much the same: everyone who is interested has bought it, of at least tried it?

Nope. The one-off ceiling is basically non-existent for practical purposes. Do I pay you a theoretical infinite amount of money to use your product for a small percentage of my income, or do I pay you a small part of my wealth for your product?

With a subscription model, there’s a point where the consumer has paid you “too much” and they will either cancel or find another solution. This is also known as churn. If your avg customer pays you for 8 months, this is a pretty good indicator of how much customers are willing to pay, but you can likely charge more for a one-off cost, sometimes 2-5x more.

Since you are likely combatting churn by finding new customers, switching to a one-off model means you can just find new customers and not worry about churn since it doesn’t exist.

Don’t get me wrong, sometimes subscription models make a lot of sense. Most of the time they don’t unless you’re selling something that has an infinite cost anyway (like immediate access to “all” movies ever made like Netflix) and would be an infinite cost for the consumer to do it in some other way. But if I can pay a contractor to build your app for less than infinite money, then it shouldn’t cost an infinite amount to use your product.

Seems to work for most video games

Does it? The servers of average video game don't last very long

Those same pay-once video games also sell season passes, MTX content, expansion packs, and in-game currency.

It's actually a fair question. The online service still has hosting and bandwidth to pay for at a minimum. Paying them once does not mean that they will be able to pay for hosting and bandwidth for the next twenty years that I expect to use the product.

For scale, I've been using VIM for almost thirty years. Twenty years is not an exaggerated number.

Graveyards manage to do this, i.e. sell once and provide maintenance for a long period afterwards.

It might make the software prohibitively expensive though.

4.5 people per second turn 18 years old. Surely you can convince at least one of those people to make a purchase every month?

One $10 - $50 sale per month won't pay for hosting and bandwidth. Not to mention developers' salaries, rent, insurance, electricity, equipment, and a few pence into my childrens' funds.

And how frequently would said license be renewed?

How about for maximum flexability we do a per user rolling monthly license.

Surprisingly, people figured this out a long time ago. When you create something substantially different from what the customer originally paid for, you sell it as something different.

Self hosting option.