I'm not so sure that'd happen, but maybe. I think if it was a system like Ranked Choice. A lot of people who, for example, vote Dem just because getting an establishment dem in the White House is the only way to get progressives even close to a seat at the table (or the equivalent for Republicans) or vote Dem just because it's not Republican. I think they would be more likely to go ahead and just vote for the Progressive or other party candidate that most aligned with what they wanted. I also think a system that genuinely provided other viable choice would increase voter turnout if more people felt like their vote mattered. That would play a huge role in altering the percentages/majorities the current two big parties have. But admittedly that is a lot of ifs, ands, and buts. In general though, i'd see that potential flaw being the case for any and all other voting systems because at the end of the day, most people do fall in the middle that is covered by establishment dems and establishment republicans. Anything on the edges would always have less of a chance of winning a majority vote regardless of the voting system.