"The paintings made between 1430 and 1500 are still unsurpassed." (easy refutation - go to sistine chapel, look up).
"What made oil paint so exciting, when it first became popular in the fifteenth century, was that you could actually make the finished work from the prototype."
This is not how people painted with oil until the 19th century. It was a very expensive medium requiring careful preparatory work, sketches, and so on.
"Most painters start with a blurry sketch and gradually refine it." - completely unsupported.
"Line drawings are in fact the most difficult visual medium" - yes, carving marble is much easier.
"When oil paint replaced tempera in the fifteenth century, it helped painters to deal with difficult subjects like the human figure because, unlike tempera, oil can be blended and overpainted." - again, this is how oil paint was used much later. At the time it was painted in thin, transparent layers that did not allow the kind of reworking you learned four hundred years later in art class.
And now we have 'Cézanne can't draw" to add to the list.
Many of your other statements about art fall more in the 'not even wrong' category - fatuous generalizations based on your own tastes, but presented as deep insights about the world.
So it is a little disingenuous of you to keep asking for people to point to specific places where you are wrong. The wrong is diffusely and uniformly distributed.