What are the biggest Mandela Effect events?

I'm very curious as to why most of the Mandela Effect are minor in the grand scope of reality. The mainstream ME such as FOTL logo, Berenstain books, Shazam movie, etc. are all very minor.

Why no bigger timeline changes, like a different country winning a certain global conflict? Do some people wake up one day and be like "What is this country called USA I now suddenly live in, in my timeline the American rebellion was put down by the British in 1776", or "What happen to the King, in my timeline the French Revolution failed and France is still a monarchy".

Granted Nelson Mandela having died two decades earlier is a big event, but people remembering him dying don't seem to follow world events closely and can't even say who was the president post-apartheid in their timeline.

As for other big ME such as organs changing place in the human body, or Japan or NZ changing location, you'd think scientists who are 100% sure something changed (because they are experts in the field of the said change occuring, and not out of distant memory) would want to investigate further and win a Nobel prize.

For people believing in timeline switch or universe hopping, or some sort of government or alien experiment, why would the main 'visible' effect be so minor?

Edit: added examples of what I mean by minor ME, as people seem to think a cornucopia in the FOTL logo is a major change in the fabric of our reality. I'm talking big events like Soviets beating the US for the moon landing or twin towers still standing