Thank you @alexrjl - I really appreciate the succinctness of your post.

To @jtm, yeah agree with the first part and towards the second - I was trying to get at that in the post i.e. there are significant risks with taking things too far/thinking too big picture without appropriate grounding.

@rogerackroyd - I like your point about utilitarians not having  to reach the conclusion I came to above - similar to @alexrjl except within long-termist utilitarianism itself, and that small likelihood carries significant weight - getting at what @jtm was mentioning.

Thanks to the others who commented as well!