What you are right of course, but the fact is that if the electoral system will work as you say, a few cities will make the decision for all of America. It's not quite right. As a financial center like new York can solve the problems of farmers of Texas? Therefore, the vote of a simple majority does not reflect the mood in society.
More honest would be votes based on GDP share. In this case progressive areas, consisting mostly of Silicon Valley, New York and Boston and will decide all US politics and leave no place for insane morons, who impose stupid legislation on creative people who contribute mostly in US prosperity.
If Texas don't like, I think it can secede from the US, just like US seceded from the UK. According to the precedent legal system (common law) spirit, it must be absolutely legal.