First of all, Bills like these won't be passed on a blanket scale.
Even if they are passed, there will be lot of modifications, lot of ifs and buts etc . Even if this Bill gets passed as it is, it has very little significance . Nobody is newly coming to USA (barring a few exceptions) on H1 visa now a days and most of the people here have already begun GC process and the remaining people will follow suit very shortly. The worst affected wil be the foreign students. If the things continue to go down in the next 3 or 4 years, then the focus will be on GC holders (to apply conditions on them for employment etc). But they can't really do anything against GC category because it is a very powerful group(millions of people).