Leftists like Michael Moore keep pushing this idea, so I presume that at the end of the day it ain’t good for our side.
The runoff election used to be common… but can work against the “establishment”. So many state parties (GOP and Dem) changed their election laws to where 50%+1 was no longer the winning formula. Such was how Clinton was elected in 1992, with only 43% of the popular vote but 370 Electoral votes. No one should win any election (IMHO) with less than 50%+1. One of the (lame) reasons for eliminating runoffs was cost... clearly much money was “saved” in the 2000 Florida recount.