A little personal anecdote:
I grew up in Central Europe and in a very meat heavy society. When I grew up I would have had three proper meals every day with meat in them. Meat was THE main component of every meal. A sandwich without some ham or bacon? Unimaginable! Lunch without meat in sauce, or steak or some ribs or some chicken? I would have taken this as an insult. Are we beggars now or what? Dinner... same story.
In my early twenties I was convinced that meat is part of a well balanced diet. People who don't eat meat are weak. They get ill and they certainly won't have much muscles. I was an ignorant prick, let's put it this way.
When I was ~25 I met my wife whilst travelling. She's British Indian and grew up her entire life on a Vegetarian diet. We got together and so on, but the point is I was confronted to compromise with a Vegetarian person from one day to another without any warning.
Initially I continued to eat the way I always did, just taking her preferences into account and try to be the loving supporting boyfriend/husband that we all want to be. I'd cook my meat in a separate pan and I'd use different knives and forks to handle meat and the veg in the house. My wife asked me for only one favour: If I could not buy beef and store it in the house then she'd be super grateful. I was okay with that, I thought cooking a good steak takes some skill anyway and I can happily just eat steak outside and cook other meats at home.
7 years later and I am 99% Vegetarian. The other 1% is sea food. I look back at myself and think how stupid was I. I feel healthier today, get less ill and feel physically in a pretty good shape. I don't take any protein shakes, supplements or other crap. I actually prefer to eat veg over meat. It all started with me trying some meat replacements like Quorn when making a stir fry, or Quorn mince pieces when making spaghetti. Then I'd start cooking more beans, lentils, chickpeas and other high protein ingredients. The taste is amazing and our meals are rich in nutrition, vitamins and carbs.
I was the guy who would have sworn that I could never become Vegetarian and today I'm almost the opposite. I don't like the look, smell or consistency of meat anymore. I don't like that it's so easy to get seriously ill from meat when not cooked properly, or the utensils which were used for preparation were not cleaned sufficiently.
Long story short, if I was able to make such a drastic turn around on make meat intake then I know that anyone can. It just takes a strong incentive to implement change. For me that incentive was being in love with a girl, but for others it might be something else. Tax, regulation, laws are an effective tool. Personally I believe that nobody will miss the meat in 20 years time if implemented by a government. It's just too difficult for people to imagine that is true and I consider myself lucky to actually have experienced this myself so I can say this today.