Boss
Take a Memo:
This industry changed the World, so I took it as an example. Maybe some rural state with a low population had just a few electoral votes - and then turned into be the backbone of the union. You explained it well below.
Okay, now I kinda get what you are trying to say here. Some state might happen to have a vital resource like oil but they have a small population. A "pure democracy" would simply rob the state of their resource by tyranny of the majority.
Another good example might be farm country... large expansive areas of land where the nation's crops are grown.... not a lot of populace but an abundance of resource. What if a popular majority in California and New York decided that Iowa should send all it's corn to them free of charge and made it a national law by popular decree? Screw the farmer in Iowa, he has no political influence because his state lacks the population of New York or California.
The easiest way to understand this is, we are not a single nation state. We are the United StateS! Plural, as in, more than ONE. So the national popular vote means absolutely nothing other than some trivial number for our amusement. Each state has to retain some degree of power in the political process or there is really no reason to have states at all.