Interesting Maps

All the places shown were part of the Spanish empire in the late 18th century, so united under Spanish rule (along with Spain itself, the Philipines, and a number of other places). Indeed the map could have shown even more territory; Spanish claims extended up the west coast of North America to the 61st parallel, well into what is now Alaska, and in 1763 Spain acquired the Louisiana Territory from France. That territory covered a huge swathe of the midwest, extending from what is now the State of Louisiana northwards into what is now Canada. 1763-1800 was the high point; Louisiana was ceded back to France in 1800 (who promptly sold it to the US); Argentina became independent in 1810, followed by Gran Colombia, Chile, etc. By the mid-1820s Spain had no possessions left on the continental Americas; they did hang on to Cuba and Puerto Rico until the end of the nineteenth century, though.

As for "taking credit" for the economies of California and Texas, California would have had gold (and therefore a gold rush) and Texas would have had oil (and therefore an oil boom) regardless of the language spoken by the inhabitants.

Tl;dr: California and Mexico didn't become prosperous because the US acquired them; rather, the US acquired them (by conquest, from Mexico) because they were resource-rich.

If Ireland and India were united tomorrow, then Ireland-India would indeed have a GDP equal to the aggregate of the current Irish and Indian GDPs. (What might happen afterwards is a different matter.)

And that's all the map is saying. It's not saying that if Spanish America had never been disaggregated then it would have the combined population, wealth, armies, etc of its various successor states. It's expressly saying that if those states were reunited now, then this would be their combined population, etc. Which (assuming they have done their sums correctly; I haven't checked) is true, but trivial, since those states are not going to be reunited. There was a reason why they disaggregated in the first place.

Except for Wyoming!

There isn’t afaik . BH substitutes for V ??