It did. It ended (when things stabilized) with the 50s and 60s.
The 50's and 60's were an aberration in the grand schme of things. The only reason it worked (briefly) was.
1. Wages doubled in the US in the war years
2. The defeated countries were in recovery, once they recovered and made consumer goods instead of weapons (cars for example), US started to struggle.
3. Certain countries were mostly excluded form the world economy (China, USSR), or were still developing (India).
4. The population was smaller, oil was easier to get (600 million benefited the most).
5. The elite made a social contract as they needed bodies for the war. A generation later the new elite/economic philosophy went in a more neo liberal direction after 1973.
What usually happens is the extreme left or right go to far left or right and the other side takes over for a generation or so. Here the old unions lost massive public support as they got paid more than most and kept going on strike with rolling strikes during times such as holiday season which annoyed everyone else who voted in neo liberal MPs who then smashed the unions power. A rolling strike is when the rail road workers might go on strike but then are joined by teachers or port workers "in support" etc and everything grinds to a halt. Part of this was also unions focused on various other causes that also did not put money in their members pockets so why pay union fees when financially you are better off not in said union. The union I was in struggled to get a 3.75% pay rise (it was technically 5% but no back pay), I left said union and got 10% and didn't have to pay union fees.
This is also why the left is getting nailed on identity politics. Its not that some people who voted for Trump are raving racist lunatics but the lefts focus on all these special interests groups (minorities) comes across as "you don't care about us and we're struggling as well". Basically if you are to rich to get government help/handouts and don't qualify for the riches tax cuts and/or tax avoidance the left comes across as annoying (BTW I voted for the left).
Most of the time left vs right boils down to who can bribe the middle class the best. If they lurch to far left/right to fast they get voted out (I suspect this is the GoPs fate in 2020).
Note that everything else we have tried since we stopped being hunter gatherers you always end up with an elite at the top regardless of social structure. Even in Communism the rich get replaced by party bureaucrats (who then become rich).