In a world where every fast food joint is vegan, this would still happen. I’m not pro meat, I just don’t like equating unrelated things. As soon as meat substitutes become profitable and marketable enough, McDs will switch to them. And they will continue to extract as much profit as they can.

Correct.

The 1st century started at 1 A.D. and included 100. 2nd century started 101 to 200. Etc etc. If you change the 21st century to be 2000. You would to shift everything down. Eventually making the 1st century 99 years. Or creating a year 0 or using 1BC.