What are 2 key reasons that the equal rights amendment might not have been ratified?

As someone who was too young at the time to fully appreciate the complexities of the political process at the time, I never understood why the Equal Rights Amendment was never passed. On the one hand, it seems a no-brainer, a basic statement of obvious human rights. However, trying to research online the reasons why it wasn't passed produces a whole bunch of feminist fruitcakery, including some who insist the amendment technically passed and is in effect. The original support for the amendment was among conservative women, while labor unions and "New Deal" types virulently opposed it an exact flip flop of the typical cliches and stereotypes of the political left and right.
My idle speculation is that the trouble stems from the second clause of the amendment as proposed: "The Congress shall have the power to enforce, by appropriate legislation, the provisions of this article." That seems, in an era when people are arguing the constitutionality of mandating health insurance coverage, a loophole big enough through which to ram all sorts of trouble.