Glass actually takes a long time to lose its sharp edge unless it's dumped in a river or the ocean, which is in fact a great way to dispose of glass.
There really is no better way to dispose of garbage than dumping glass in the ocean... returning silica to its source in a way that doesn't look bad.
No, over time the plastic bottle will weather into cell-scale microplastic particles and play indefinite havoc with local wildlife. Glass will not.
Of all the things that got dumped onto this beach at Ft Bragg, glass was the least problematic.
https://en.wikipedia.org/wiki/Glass_Beach_(Fort_Bragg,_Calif...
Especially when a critter chews on it accidentally, or it gets crushed under foot and some ends up in the foot.
It's the dulling process that sucks.