Honestly this just shows that something I heard about Unity getting more anti-developer and just going for cash being completely true and is truly a stupid move as it pushes everyone to Unreal since that's the only other well known dev engine that's newbie friendly without much time investment. Though there are other engines too yes. Unity made an Youtube kind of move and beyond.
This is one of those things though that sadly due to it being done retroactively it won't be easy to protest off the bat to cause changes, it needs sustained protest which sadly a lot of devs I doubt can do since they've done a lot of time investment into their game and may not want to restart all over with another engine they don't know how to use yet.
I wouldn't be surprised all in all if devs quit/go silent to switch to Unreal or just continue on. Though cracks of Unity to remove this function will probably start to appear over time or DRM to be heavily implemented so devs avoid the pirates more.
EDIT: Did a quick search and found an Verge article that gives further information and explanation but to me it makes it clear that the situation is worse than above and even more dumb of Unity because: Subscription Services (e.g. Xbox game pass) charge the service owner (e.g Microsoft) instead of the dev. So I'd be surprised if Unity doesn't receive complaints or slaps by the big distributors once they realize why they're getting billed millions if not billions. It is a way for most devs to avoid this charge although Steam and maybe GOG would be the only places that would accept the games onto them if they do continue to after this change hits without implementing an kinda "download fee" which I wouldn't be surprised if the Epic Store puts in.
Also although game Demo's won't charge the dev this is only if full game isn't included in someway (no idea how they're going to detect that). Finally and most hard hitting is early access titles is not counted as demo's but considered to be the full game and thus hit with full price.
Now there's one extra thing that's going to probably cause more upset when realized.....as the Devs (on Unity Personal/Plus) are going to get charged 10x more when their game is installed in an "Western" country instead of an "Emerging" country like China other Asian area countries no idea what causes a country to be declared as "Emerging" economy wise by Unity. So selling the game to Emerging countries is overall better as if they spend the same amount of Dollars overall than a Western country the Devs get massive discounts compared to selling to Western countries as their fee's stay the same no matter how many installs occur, while Western country install cost only gets reduced fee's via Unity they got and install count. (1 million installs AND having Unity pro/enterprise results in the lowest fee for Western installs which is the same as Emerging installs with Unity pro)
See the image below to see the boundaries and such.