This discussion was had when the original 13 colonies made a decision, for the second time, to unify under a single federal umbrella government.

After the complete failure of the Articles of Confederation, a second initiative was created to desperately try to get the 13 states to subjugate themselves to a collective government. They all wanted the benefits of this shared collective, but had various gripes about joining it.

The biggest gripe:

At the time of the drafting of the Constitution, Virginia alone had over 20% of the entire population of the US. New York and Pennsylvania were also populous, compared to states like Delaware, Connecticut, South Carolina, etc.

The original design of just having a purely population-based House of Representatives (and Presidency) was immediately rejected by all of the smaller states. Only the big states were ok with that. The smaller states were unwilling to join under an umbrella government that could be fully controlled by two or three populous states, at the expense of the interests of their own citizens. They immediately rejected the Constitution. This resulted in the creation of the Senate, and it's role as being the UPPER body of Congress, with more power than the House of Rep.

Without removing the pure popular vote, the union could have never been created in the first place, because it was immediately viewed as a way for populous states to subjugate less populous states. And those states and their citizens were unwilling to take that risk.

When you understand that this system was DEMANDED by smaller states before they were willing to join the union, you quickly realize why removal of such a system would likely result in some form of gradual disintegration of the union.

The system now makes it so liberals in Mass and rednecks in Wyoming occasionally get people that match their beliefs running the Federal government, with cycles of fury from the losing side every election. Abolishing the EC would have the near-term effect of having one of those groups, the one that dominates large, sparsely populated states that control most food production, become perennial losers, in a permanent and unending fury at a government that doesn't listen to or care about them. If you want to understand what this looks like, go talk to your average voter in upstate New York, whose state government and tax policies are dictated by NYC voters who are mostly renters. Do you think upstate New York has similar needs to NYC? I can guarantee they don't, and those needs are unaddressed. Ditto for voters in southern Illinois. The animosity is palpable, and that's for neighbors a hundred miles away.

Eventually, states will secede. And in a modern world like ours, I don't think it would be dramatic and violent. Likely just modern secession referendums.

The current conversation about abolishing the EC has always been a partisan power-game, just like giving DC statehood. If the conversation around DC statehood were actually about representation, rather than 2 new Senate seats that are guaranteed to represent city-dweller interests, the Congressional Act that allocated land from Maryland to be DC would simply be reversed, with the land ceded back to Maryland, and the addition of two new Congressional representatives to Maryland. This is exactly what was done in the 1800s with the unused portion of land Virginia allocated to form DC with Maryland. (the Virginia side of the Potomac was ignored by Fed gov, so the residents demanded to be rejoined with Virginia, and they were.)