I think their general plan will be to discourage/silence influential left-wing voices with enough cover to keep the majority of the audience for an emboldened right-wing.

If thinking imaginatively, then the proposal framed as "$8/mo or have your tweets deranked" is a deal they actively don't want left-wingers to take. They want to be able to derank their tweets with a cover of legitimacy.

The more they can turn this fee into a fee into a controversial "I support Musk" loyalty test, the more they can discourage left-wing / anti-Musk subscribers while encouraging right-wing / pro-Musk subscribers who will all have their tweets boosted.

Feels conspiratorial but it's a fee that mostly upsets existing blue tick celebrities which should be the last group Twitter The Business would want to annoy but they are the influential left-wingers. If you look at who Musk picked fights with about it e.g. AOC and Stephen King, then that is even more suggestive of deliberate provocation.

Whether planned or not, I suspect that this is how it play out.