I'm fine with it if includes some monthly re-occurring service, like cloud storage/sync.
I purchased YNAB4 and I ran it just fine on my desktop. But YNAB5 went to subscription, and it included things like syncing multiple devices (which of course needs servers, which cost), but I have no need for that, and so I did not move to it. I'd much prefer I pay some one-time fee, and if I want syncing I can subscribe to just that.
I also understand that if I pay $x for Version Y, then if I want Version Z there may be an upgrade fee.