They should have a Marxist ideology that is friendly to a large part of the population or marginalized groups in order to achieve relevance.

Adapt new technologies to their ideology and not come into conflict.

This article explains it better, although it is from 2017. Link

And the MAGAs are against big business, just like some of the Democrats.

Well, the general form of Marxist ideology in the population is not so much. But some elements of this ideology are so strong that the Republican Party uses this model of discourse for its voters.

An ideology has to evolve over time in order to remain relevant to the generations that come and go from time to time. If you don’t do that, you will stagnate with a small group of people.

To gather more people, you have to find a common ground of the groups that are marginalized from society at that time, and you have to lead them to achieve that goal.