What’s worse is it used to be 90 days. Apple changed it to 7 days years ago.
That, in their opinion, makes it their job to prevent people from permanently installing software on other people’s phones. I’m sure they would remove the “permanently” if they could, but developers have to test builds so frequently that they can’t review them all.
There are simpler and more usable options that are more defensible than what they do today.