Thanks; this is much more concise than I could manage.

I think the key idea is fixed minimum/maximum boundaries for a lot of astrophysical phenomena—stellar protium fusion, the Chandrasekhar limit, Tolman–Oppenheimer–Volkoff limit, etc.

It should have been obvious to me (fusion duh!) that the result of the fusion is a higher density material that then increases the conditions for the reaction to take place. Both comments were immensely helpful and interesting! Thank you.