There is zero rationality behind the decision, especially given that it’s retroactive and there’s no language in their decision that handles unique user versus multiple users versus multiple accounts.
I’ve had two gaming PCs over the last ten years. On my last one, I replaced the hard drive twice, and I’m on my second hard drive on the newest one. With each hard drive replacement, I’ve had to reinstall all my games. I’m not paying for all of them again with each install but just getting the same files off Steam and installing again. According to this decision, the devs of these games would have had to pay Unity four extra times just due to my hardware upgrades. How is that on the developer at all, and Lord help us if Unity tries to run some BS where players have to pay for each new installation.
The entire gaming industry, even from the “disc era”, doesn’t work with a cost per install model.