Why aren’t plane cabins designed better for turbulence?

Maybe a stupid question. But I’ve always wondered why:

  1. They don’t design planes with stronger luggage compartment latches so they don’t pop open and send heavy luggage flying during strong turbulence.

  2. Install better seatbelts (the kind with padded straps that go over both shoulders), to prevent people from flying up into the ceiling and sustaining serious injuries.

  3. Install a seatbelt in the bathroom. Undignified, but if I got caught in the bathroom during sudden turbulence, at least I’d have a seatbelt to prevent injuries.

All sorts of other safety measures they could employ, like airbags, for example. Why not? Greed?

EDIT: Thanks for the responses. There are some things I want to clarify because some people are assuming that I’ve been influenced by movies.

I was on a flight with strong turbulence about a decade ago. Bins fell open and luggage was flying around. People were flying around. I am a small, thin woman and I didn’t feel secure in my seatbelt even though I had it pulled as tight as possible. I later learned there was a passenger in the bathroom who hit their head pretty badly. They were in the bathroom because the turbulence happened without warning.

This experience scarred me and I have horrific flashbacks. I know my experience was not common, but my questions are not coming from a place of complete ignorance. I am one of the unlucky ones.