It makes no assumption about an elite ownership class at all. It merely assumes profits, and rearranges how those profits are distributed (away from shareholders, towards labor). There is no need for community ownership of the means of production (though that might have some different benefits, along with some different disadvantages).
You need high marginal (or maybe not even marginal) corporate taxes and a committment to the concept of UBI. Who owns the companies, from the perspective of UBI, is immaterial.
Community ownership does not share the productivity in sector A with workers in sector B. UBI does.
Also, you haven't really answered the point. You may be able to get this established. But how do you keep it established? How do you keep the elite ownership class from dismantling it? (Based on historically observed behavior, the default assumption is that they will try.) If you don't have a plan that accounts for that, you don't really have a workable plan.
But saying that the existence of an elite class implies regulatory capture is a step beyond that.
Regulatory capture is absolutely a problem. While one could advocate for eliminating the elite class (e.g. wealth taxes, confiscation, execution ... as you wish), I'd probably go for tightly controlled political donations & spending, combined with a strong anti-corruption culture (which has been severely damaged by, ahem, recent administrations).
(a) sufficient political donations/bribes to get lawmakers to draft suitable language themselves (or via their staff)
(b) a combination of political donations and a worldview on the part of lawmakers in which it is "just normal" for those affected by regulations to draft them, such that you yourself are able to draft the legislation.
There are levels of government where neither of these require incredible levels of wealth, I suspect.
Both could be stopped by limiting political donations and a political culture in which "the chemical industry writes its own rules" is self-evidently corrupt and/or non-sensical.
Whether any of these require incredible levels of wealth or not is moot, I think. The reason for that is that it only matters when 'lesser levels of wealth' come up against 'greater levels of wealth' and the latter will always win that confrontation.
It's effectively liberals seeking a liberal solution to mass starvation and obscene wealth inequality, they see a soon to be trillionaire like Musk alongside children starving on the street and try to find a solution within their narrow world view that demands the protection of capitalism, that's how it ends up so incoherent. It's same with the 'abundance movement' it's neoliberals seeking to fix neoliberalism with more neoliberalism.
Don't expect much clarity from these people, they are deeply confused and propagandized, to them their workplace is ought to be like family, collective bargaining is viewed as breaking the mutual trust you should have with your bosses. It's gibberish.