Billionaires are only rich because people buy what they sell (abstractly speaking, there is a lot of nuances here).
If there are no people, then money/wealth becomes moot.
The goal is to reduce the overall population and enhance control over those that remain. The biosecurity state and control over energy consumption are key points in this agenda.
After you can buy everything you could reasonably want, what other avenues to expanding your status remain? There are things which money alone cannot buy.
https://www.corbettreport.com/gates/
https://www.corbettreport.com/episode-286-rockefeller-medici...
https://www.corbettreport.com/bigoil/
To the point of the original poster, the entire agenda is largely framed by billionaires and their globalist institutions. The World Economic Forum, the successor to the Club of Rome would be a prime example. Note the connection to the seminal eugenicist, Malthusian manifesto "Limits to Growth".
https://www.clubofrome.org/publication/the-limits-to-growth/
All of these agendas make more sense when the historical and ideological backgrounds of their promoters are better understood. Of course, this does not packages as well as fear mongering soundbites portending an impending apocalypse.
[1]: https://en.m.wikipedia.org/wiki/How_to_Avoid_a_Climate_Disas...