"Often" != "Always". Therefore you also agree that solar still competes for land use with crops.

Furthermore, land that has already been allocated to grid scale solar has already been taken away from possible crop use. Sometimes it's not arable land, but that isn't always the case, therefore solar is still ostensibly taking up land that could be used for crops.

Finally, I even disagree that somebody knew that solar and farming could use the same land. Someone had an idea that maybe they could coexist, then ran an experiment that succeeded. They certainly didn't know the outcome beforehand.

No. It just means that some places are better than others.

Since there is overwhelmingly more crop and pasture land than could ever be needed to satisfy power needs, solar may be placed exactly and only where it does the most good.

It has been known for centuries that most plants benefit from partial shade. It is an exceedingly tiny step of logic to go from "shade" to "shade provided by solar panels". In the past, providing shade just cost money. Now it yields direct revenue, year-round.

Again, "most plants" does not necessarily include "crops", most of which have been selectively bred over millennia while grown under full sun. The step is not from "plants do well under shade" to "plants do well under solar panels", it's to "crops we've never grown in partial shade might actually do better in partial shade too".