Only because from my understanding is that if I convert the license to monthly payment, and then i forget to update my CC in a year from now when it expires and i am on vacation or sick or anything other, then my server would cease to work or atleast my control panel/access to my server would cease? That would be a total disaster and too much risk. For me, the essence of DA is to give us the power over a server, not to hand power of my server to a subscription plan. If i am missunderstanding the subscription, then that is totally my fault.
I dont know if you use software like phpstorm/idea products or Apple Developer program for iOS apps is similar. you pay a fee and that gets you what is available at the time. If you stop paying then what you already pay for doesnt break, it just continues in its old form. That is what the lifetime license is like to me right now, which is perfectly acceptable. The same concept translated to DA would mean no more new installations with that license unless your license is paid for and up to date at the time of install
The difference between DA with phpstorm or Apple is with the later two I can just pay for another year and move myself forward with my license and get the new updates or make a new installation or whatnot. There is no subscription required. With DA I cannot do that, I have to switch to the risky subsdcription model (unless my original understanding is incorrect, then please ignore