I’m a big fan of JetBrains model for this. Buy the software on a subscription, and the subscription gets cheaper for the first 3 annual renewals. While you’re subscribed you get access to the most current version and when you stop subscribing you have a lifetime license for the latest major version (and it’s patches) that you’ve paid for at least a year of. The subscription helps fund the continuous development that is expected of modern software but you still get to keep something for having invested that money when you’re done.
As a customer, so many frustrating things boil down to not being given a choice. Not even having a tickbox to express which way you'd like it even if the default is otherwise.
Pay for the major version, get all of its updates. Then pay for update (to next major plus its updates) with a discount.
If you don't prefer the pay, you can keep what you have.
This is what Reaper, Forklift, CameraBag and countless others do, and it works very well.
Edit: This comment contained Forklift as an example before, but they have changed their model, so it's removed.