Why say 'longtermism' and not just 'extinction risk'?

Summary

The thinking behind the title:

• Achieving longtermist goals depends on avoiding extinction in the next 100 years.
• Extinction risk in the next 100 years is sufficiently high that the longtermist movement should optimize almost entirely for reducing it.
• Reducing extinction risk is a subset of longtermism, so more people will be convinced by an argument for reducing extinction risk than an argument for longtermism.
• Why not focus on the 'reduce extinction risk' argument that more people will be convinced by, and that is almost all of what longtermism is concerned about anyway?

Example: Will MacAskill and Tyler Cowen

This post was inspired by recently listening to Will MacAskill on Tyler Cowen's podcast (link). Tyler raised a few reservations about longtermism (phrasing below is my own):

• Does consequentialist reasoning break down on questions about extremely large populations?
• Similarly, isn't consequentialism inadequate for explaining the difficult-to-measure value of things like arts funding?

If instead of defending longtermism, Will was just defending reducing extinction risk, I don't think a single one of Tyler's reservations would have even existed in the first place.

Recent press around the movement is focused more on longtermism than reducing extinction risk

Here are a few examples: NYTimes, BBC, Time, Vox. 

If longtermism cares about making a case that is compelling to a larger number of people, I think it should emphasise 'reducing extinction risk' in its public relations.

For what it's worth, I suspect that the majority of readers will find the framing of longtermism in the above articles either interesting but forgettable, or abstract and offputting. 

Admittedly, I am not a journalist, and maybe framing things in terms of the enormous potential for future life in the universe is actually a better way of getting people inspired and excited than talking about extinction (i.e. point 3 of my summary is false). I can at least observe that this isn't a typical journalist's strategy for convincing readers an issue is important. I would be interested to hear more qualified opinions on this question.

Possible concern: do people say 'longtermism' and not just 'extinction risk' because it's more interesting?

I think philosophical writing on longtermism is valuable, and I also value intellectual curiosity for its own sake. But I think promoting discussion of 'reducing extinction risk' over 'longtermism' in public spaces is a more pragmatic way of both getting new people involved with longtermist issues and achieving longtermist goals.