In addition to the issues raised by other commentators I would worry that someone trying to work on something they’re a bad fit for can easily be harmful.
That especially goes for things related to existential risk.
And in addition to the obvious mechanisms, having most of the people in a field be ill-suited to what they’re doing but persisting for ‘astronomical waste’ reasons will mean most participants struggle to make progress, get demoralized, and repel others from joining them.
My gut reaction was to be surprised that there are whole fields or causes in which some people not only aren’t a good fit for the most important roles there but that they just can’t use their skill set in a constructive way in which they would feel that they are making some contribution.
But on second thought, we are talking about extremely small fields with limited resources. This means that it would be difficult financially for people who aren’t skilled in accordance with the top needs of the field.
Then again, the field might grow and people can upskill quite a bit if they are willing to wait a decade or two before working directly on their favorite x-risk.