Fact is most of these protections have been a matter of law in several areas of the country for well on 25 years now. Though far from 'all' states, the existing laws cover about 75% of the population base. Nothing about this is going to change much in LA, or NYC, or SF. It will, maybe, eventually, change some stuff in rural areas like Mississippi.
Oh, and most of those laws address the problem by defining who goes go what bathroom by presentation.
Of course it's easier for nations with less population (NZ would rank, as a nation, about 14th or 16th or so (depends on who is counting) in US metro areas, or about half the population of either of the two largest urban areas, about the same population as Minneapolis, or San Diego, which is only California's 3rd largest area) and less land area to govern.