Not so much lately.
These major parties don't represent tiny segments of the population with sometimes radical views, which is often the case in proportional systems.
The two major parties aren't tiny, but they are more polarized than major parties in other countries. Many countries have a mixed system. Some representatives are chosen by district on a winner take all basis. Others are chose proportionally from the lists the national parties provide. So it's not a matter of choosing between a purely proportional system and what we have now.
Israel is an exception in so far as it has a purely proportional system and a low 3.25% threshold for receiving a seat in the Knesset, its legislature (there is also no upper house). Other countries with mixed systems and higher thresholds don't have such problems. Minor parties in a governing coalition in those countries can get their way on a few limited issues, but the countries aren't suffering much for it.
Rather they represent an America that is shaped by different regions with their distinct broadly-accepted values.
A system with big parties that represent different regions with opposing values is not necessarily better than a system in which small parties represent smaller constituencies, which can combine with each other as they see fit. The traditional defense of the two party system was that it reduced polarization and produced moderate outcomes. That really isn't the case any more. True, the outcome is usually a stalemate, but the divisiveness and animosity grows and grows.
Proportional representation would be an unmitigated disaster in the US and a boon to the left. The far left wants it.