Why not? Thousands of app companies exist on one-time payment for many years, releasing payed updates sometimes. MacPaw is a good modern example.

For a solo developer a one-time purchase model can do pretty well. 60 million+ Mac users is a big market. Speaking from experience.

A desktop app with no server component doesn't necessarily need aggressive monetisation because at a certain point it reaches feature maturity and doesn't need much more work. It sells itself while the developer works on other things.

Of course if you're looking to go beyond a "micro-isv/lifestyle" business and want huge growth it's a different sorry.

You charge for significant version upgrades. The industry was OK with that model for decades before SaaS became feasible.

Very soon having a big monthly software bill will be seen as normal. This makes me sad. Don't we have enough recurring bills as it is?

Hat tip to the software author for showing some morals and not trying to bleed consumers dry with a monthly service cost for something which is not a service. He has just won some custom from me.