They have all the right in the world to do so, but I have a lot of trouble with them insisting that this is “not a subscription”. Let’s call a spade a spade. It’s a subscription to get updates, with a perpetual fallback license. The only difference with JetBrains’ model, which offers the same for their IDEs (which everyone calls subscriptions, themselves included), is that Unraid still offer a lifetime tier on top. But the lower tiers absolutely are subscriptions. If it was really a “version upgrade” thing, they’d tie the payment to major versions, not a time period. It’s a time based payment in which you get something in exchange during the payment period, therefore, a subscription. The word may have connotations for them to want to avoid it so much, I won’t pretend it’s not what it is…
Otherwise, for what I actually use Unraid for, they just put themselves out of my price range and it probably won’t be my next NAS’ OS. Outside the “use any disk size” RAID-like solution, there isn’t much keeping me on the OS, and I guess I can deal with setting up MergeFS/Snapraid…