But then Star Wars was envisaged as a series of films and the sequels and prequels are part of a directly related story with overlapping characters and pacing, with the original creators around to give it their blessing and the occasional bit of creative input. Fans can overlook a lot of shoddiness to see C3PO again or how Darth became Darth. The forging of rings or founding of Rivendell, not so much, and I think the story of how Gollum became Gollum is off limits to the series too.
The Amazon LOTR proposal is basically some new fantasy stories set in a different millennium from the LOTR world which loosely tie in with some chronologies Tolkien wrote as lore rather than narrative, with a license which prevents them from reinterpreting events from the LOTR/Hobbit books from a Tolkien Estate that isn't exactly keen on giving the series canonical status. Instead of hobbits from the Shire and kingdoms of Rohan and Gondor under threat - all places that don't exist, never mind the characters - we've got a blank slate fantasy civilisations called Numenor and Eregion (which will resemble LOTR in the same way most high fantasy civilisations tend to) and a pretty loose narrative arc which implies the bad guy eventually destroying them.
The output might be very good stories in their own right, or it might be bland as hell, but the hardcore Tolkien fanbase is going to be hard to please. Create a series of episodes purporting to show the full history of the Second Age and it'll be [probably correctly] accused of being disjointed and completely lacking Tolkien's epic storytelling skill; create a compelling quest narrative involving dwarves and hobbits and it'll be accused of discarding Tolkien's actual histories in favour of a cheap knockoff of his plot structure.
I mean, a licensee could probably randomly choose a third rate LOTR fanfic plot and sell millions of tickets to watch it, but that doesn't necessary mean its a good idea from a creative standpoint.