Hi @scienceangel ... First, please accept my apology. It seems I did exactly what the OP warned against doing... Writing with a self-righteous tone and thus alienating you. Sometimes it is difficult to stay level-headed when discussing this topic. I'll now try answer anything I missed before.
I agree with you that no matter what, life will choose to survive rather than go extinct. Human individual life, in extreme cases, might choose suicide instead of continued suffering, but in general, and especially with animal life, usually survival trumps all if it can help it. So I was wrong on that point.
In your hypothetical scenario, where everyone suddenly stops eating meat, you say that then the animals would suddenly be let go to roam free and all probably die. I don't think it would happen that way. It would happen gradually, with the breeding/killing system slowly phased out in favour of better options (in-vitro meat is a thing and as soon as it gets cheaper, will probably be adopted by big companies). The animals, as I said, will still be in demand as pets and some people will always prefer "natural" meat, but I see it becoming a novelty, and much more expensive. Farming might continue in this way, on a smaller scale, and the animals will probably live much better quality lives. So it's not likely that they'll go extinct.
If they do go extinct however, despite our best efforts to prevent it, I feel that morally, this would be better than us consciously causing the suffering of billions of animals every year.
I believe I've addressed the salient points in your response? Please let me know if I've missed something.
And again, sorry for the typical vegetarian self-righteous response before... Not sure if it deserved that mocking laughter GIF though ;P