@Wendell: your post last page is frankly too massive to give it a proper answer, if you have any points in particular you'd like me to reply to, please mention those specifically.
Without the USA, Europe would be either Nazi or Soviet by now.
With over a century between US independence and the Russian Revolution, there is enough stuff happening differently that it's not possible to conclude there
would be Nazis or Soviets.
So, historical events are inevitable?
Depends on timeframe and scale and so on, I'm probably not going to avoid a great war between European powers by thwarting Franz Ferdinand's assassination given the geopolitical tensions in the background, but that version of WW1 would probably be unrecognizable to OTL. Likewise, it's not very likely that averting the US revolution in the way presented in the OP (he mentions "Britain [holding] on to the Thirteen Colonies", so we'd assume there is still a similar revolutionary war happening) would still lead to French bankruptcy and socioeconomical strife leading to some form of revolution. A scenario like "The UK peacefully reaches an agreement with their colonies, defusing the situation before revolution" might avert the French Revolution by leaving France's finances in better shape.
Why is it extreme likely even without the American Revolution?
Because the socioeconomical conditions in France and Europe at the time of the French Revolution make it likely to have an uprising against the French monarchy.
Does no Columbus mean America is never discovered?
You'd have to ask
Leif Erikson. Or, better yet, the many civilizations that lived in the continent before any European set foot there.
Less condescendingly, the route that Portuguese ships took to reach India went very near to the coast of Brazil, so one unfortunate storm at the right time and you get a Portuguese discovery of America in the early XVIth century.
I've never said it was the sole cause. If you're not going to read my posts, why should I bother engaging further on the subject?
You're moving the goalposts now.