Seems like we’re stuck in a loop here then. I think you need an engaged populace first to build momentum around political and societal solutions. Which society do you think will force the government to actually solve the problem - a bunch of soft apathetic people blaming everyone else, or a society that at its core actually values sustainability and lives it on a personal level? Pretty sure you know the answer.
How can you possibly think the US military, or any sovereign country, will magically spend an extra $165B a year on meat a year if all of the current consumers magically go vegetarian? Who exactly is going to eat a bunch of extra meat? There will just be fewer meat sales, period, ignoring a short term price drop if everyone magically goes vegetarian on the same day.