I do not yet have Roon but intended to buy a lifetime sub if and when I did. As I procrastinated, I fully anticipated such increases.
For all the reasons stated, lifetime subs make sense for upfront capital, but make increasingly less sense as growth happens.
As an aside, I dug deep to afford a lifetime subscription with an advisory service some 15 years ago. I was relatively young. I worried it was far too much at the time. A lifetime subscription now is about 5 times that amount. And still considered a bargain by most estimations.