A drummed up fad with more content, picture/audio encoding is uncompressed (Most of the content even when compressed higher quality than streaming), higher bit rates, Internet restrictions, no need to find content where the future will be needing a separate subscription service for Nextflix, Hulu, the Disney’s service that is coming, whatever Movie studio wants to secure their own service/IP, etc... each month, some people like the special features as well.
Not much of a fad if you ask me especially if the top movies of the year are still pushing over 1-4 million units sold (BR) in the US in the age of easy pirating and streaming options.
DVD was just fine. There was no demand for Blueray. They invented this fad where it wasn’t even needed and fools fell for it. There was absolutely no reason at all they should cost twice what a DVD costs. It was a marketing scam from the get go.