I'll try to make this as simple as possible...
They don't because they are not selling everything to people like you.
I have more high end basses than most people... I've been fortunate that way. They are all in excellent condition and they all go on gigs. Lots of gigs. LOCAL gigs that do not require the instruments to be out of my sight.
Can you even imagine this scenario? Apparently not.
BTW none of them are Sadowskys. So much for this zealot nonsense. This is more fundamentally silly that just thinking it's tied to brand loyalty.
My F Basses are in factory bags. So is my Fodera. Maybe you can go after them next.
I'll make it even simpler...
I DON'T LIKE HARD SHELL CASES!!!
They're typically bigger and far clumsier than any of my gig bags. The Tolex covered HSCs I've seen aren't very durable. So why should I buy one? All of the basses I've purchased new came with a HSC... and I immediately put them in the closet.
Define "real" protection? Are we talking minor mishaps or really boneheaded moves? Falling off a chair or OMIGOD IT'S A METEOR!!!?
The Ultralite cases are typically Cordura (same as gigbags), foam and a couple of sheets of cardboard. I'm sure it's really good handmade cardboard but still...
They don't call them shipping bags, they're GIGbags.
I gig. A gigbag is perfect for what I do.