This is a good point. :) I added an additional objection to the piece.
As an empirical matter, extinction risk isn't being funded as much as you suggest it should be if almost everyone has some incentives to invest in the issue.
There's a lot of "extinction risk" work that's not necessarily labeled as such: Biosecurity, anti-nuclear proliferation, general efforts to prevent international hostility by nation states, general efforts to reduce violence in society and alleviate mental illnesses, etc. We don't necessarily see huge investments in AI safety yet, but this will probably change in time, as we begin to see more AIs that get out of control and cause problems on a local scale. 99+% of catastrophic risks are not extinction risks, so as the catastrophes begin happening and affecting more people, governments will invest more in safeguards than they do now. The same can be said for nanotech.
In any event, even if budgets for extinction-risk reduction are pretty low, you also have to look at how much money can buy. Reducing risks is inherently difficult, because so much is out of our hands. It seems relatively easier to win over hearts and minds to utilitronium (especially at the margin right now, by collecting the low-hanging fruit of people who could be persuaded but aren't yet). And because so few people are pushing for utilitronium, it seems far easier to achieve a 1% increase in support for utilitronium than a 1% decrease in the likelihood of extinction.
We don't necessarily see huge investments in AI safety yet, but this will probably change in time, as we begin to see more AIs that get out of control and cause problems on a local scale.
Once we see an out of control AI it's to late to do AI safety. Given current computer security the AI could hack itself into every computer in the world and resist easy shutdown.
When it comes to low probability high impact events waiting for small problem to cause awareness of the issue is just dangerous.
In a recent essay, Brian Tomasik argues that meme-spreading has higher expected utility than x-risk reduction. His analysis assumes a classical utilitarian ethic, but it may be generalizable to other value systems. Here's the summary: