I too have been saddened that BluRay releases are now few and far between. I was buying a lot of them a decade ago of favorite classic movies from the mid 20th century, but now they're hard to find. I'm thrilled to have All About Eve, Valley of the Dolls, Guess Who's Coming To Dinner, etc., etc. all on BluRay.
But I wish the studios would keep it up, even in limited numbers for us collectors. Well, I'm not a "collector", I'm just an oddball with questionable taste in movies. Even the more expensive BluRay format doesn't seem to pencil out for the studios now. But just try finding
Airport '75 streaming anywhere! I can't!