This is demonstrably untrue though. There's no conspiracy, intersectionality is growing, because it's a useful framework for finding similarity and solidarity across boundaries that used to be sharper like race, language, disability, religion.
The claim makes no sense, this is not how attention works. If more people are thinking and talking about something there will be more energy and attention on it for that time, not less.
(That's why the title is terrible: It dissuades anyone left of Joe Biden from reading.)
Note that the presence of non-white Trump supporters doesn't invalidate the premise. No one is claiming Trumpism is only and exclusively white identity politics, but that is certainly a core motivating factor behind the movement.
Lots of Hispanics and Blacks in that group, who surprisingly aren't that keen on Trump
[1]: https://www.politico.com/news/2021/11/04/latino-poll-virgini...
There are also alternatives positions: anarchism of many flavours, the singularity people (post-scarity ideology, effectively - I like Manna [1] for a practical example - it's functionally equivalent to "fully automated luxury communism"), the degrowthers, the urbanists, the social democrats, the solarpunk types, probably a bunch of others I've left out. There's no limit to the number of futures being imagined on the left. There's lots of future-imagining on the right too, but the qualifying trait of the right is that their future is the same as the past.
If you mean that western humanities have adopted Marxism as in the Soviet or Maoist visions of Marx - they haven't, by and large. They're mostly onto critical theory now, which is really interesting because it's a systems analysis of societal structures. Marx did a systems analysis of capital, so many critical theorists are also Marxists, but that's about as far as it goes in terms of their direct relation.
As far as "not working" goes - trade unionism brought us many workers' rights, the 40 hour work week, and is the only thing big businesses are really afraid of. Marxism-Leninism was a massive failure, but the anarchists called that one in the 1920s.
Who said anything about the Frankfurt School? Mao Zedong quite literally tried to invent a new communism, and his Mao Zedong Thought was subverted by Lin Biao and the criminal Gang of Four to launch the "Great Proletarian Cultural Revolution", which called on educated youth to "destroy everything that's old and bourgeois and counter-revolutionary" in Chinese culture and society. These ideas were quite impactful among Western lefist radicals in the late-1960s and 1970s, and a zombie version of that Western-Maoist ideology is what survives today as "wokeness".