You are assuming the "yeomanry" mainly consists of the old, but I think that's an overly narrow and basically false assumption. The participants in the yellow vest protests in France - largely members of "yeomanry" I would think - are as much Gen X and Millenial as they are Baby Boomers.

As for the oligarchs, there are certainly wealthy individuals entrenched in the traditional fossil fuel industries, but the number of these individuals is dwarfed by the oligarchs in Media, Finance, Government, Technology etc, who are much farther removed both in business and culture from traditional modes of energy production and as such are able to take and advocate for radical positions on environmental policy without regard to the consequences for the "yeomanry".

This story plays out across the spectrum of issues that society contends with today. In general, sometimes for the same and sometimes for different reasons, elites in the corporate world and also members of the "clerisy" both desire a breakdown of traditional society to further their own agendas. In the case of the former that agenda is defined by profit seeking and in the case of the latter it is defined by philosophical and social beliefs.

So you see, I think while this piece is vague and steps on its own toes at points, it is addressing a real conflict that exists and is growing in contemporary society.