Good point. Paper straws are probably as cheap as plastic if we can get the assembly line for them up and running in the mass quantities they used to be produced. But then, that wouldn’t make any money for kickstarter hipsters, would it?.
I looked, too, before I commented upthread. Nearly all the “500 million” quotes are without a citation, and those which have one point here-
http://www.ecocycle.org/bestrawfree
-which appears to, shall we say, lack mathematical rigor.
Already out there, we use them at home in these.
https://www.amazon.com/Water-Bottle-Accessories/b/ref=dp_bc_4?ie=UTF8&node=2403094011
But if fast food joints gave them away with the drinks, they’d mostly still wind up in landfills. Paper is the way to go.