The key here is that it’s a vote for the most popular of the 2 candidates based on the votes of who bothered to vote for them specifically, then further butchered via the EC. It’s a smaller, different pool of people that may elect someone that the actual majority prefer less, because part of the actual majority decided to play a different game entirely.
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.