Perfect storms. There was a very powerful consensus behind the ratification of Prohibition, followed by an almost equally powerful consensus that it hadn't worked. There had been decades very strong moral arguments being made to prohibit alcohol: that alcoholism was destroying families, lives. They were made by well-organized groups, with very articulate speakers, that had very strong connections to churches at a time when probably most people were connected with a church, so very strong national networks. And the arguments against it seemed cowardly- taking away the workingman's beer, hindering commerce, keeping the government out of people's lives- at a time when there had already been notable reforms in the Roosevelt-Wilson years in public health matters like the selling of food, and drugs. Look through Temperance songbooks of the era, and you'll find a very potent mix of Christian fervor, patriotism and moral indignation, and it must have been hard for any politician to stand against it. Some controls were also already in place, because of war rationing.

Soon after it was implemented, however, it became apparent that it wasn't working. Not only were people able to get booze, but it became fashionable to actually be seen drunk. There were many loopholes in the law- alcohol could still be sold by drugstores, as a drug, or as cough syrup; churches and synagogues could still use it. Bootleggers could easily bring it into the country: legit foreign companies, like Seagrams in Canada did quite well, but profits from bootlegging funded criminals, paid off politicians, policemen. By 1930, some of legit alcohol businesses in the country could also begin to argue for repeal, it was obvious people were getting drunk even more than before, some of the most effective Temperance speakers were gone, and the country was dropping into the Depression and had other things to worry about than chasing bootleggers.

But yes, it is hard to imagine any pressing issue today that would get a constitutional amendment so easily; that, for example, Kansas and Massachusetts and South Carolina would be able to ratify the same amendment that dealt with campaign finance or voter registration.

Daniel Okrent's Last Call is a pretty readable recent history of Prohibition.

I can't address the core question, but I want to challenge the assertion in the second part of your question, at least a little.

There's a 13 year gap between the ratification of the 18th and the ratification of the 21st. Amendments tend to take about 2 years or so to get from an accepted proposal to a ratification, so it's at least a decade to rethink.

The second to last amendment passed, the 26th in '71, was the quickest so far from proposal to ratification. And while the last amendment passed, the 26th, is an odd duck for so many reasons, it getting finally ratified was in large part a lone person's letter writing campaign, which should speak to the difficulty. Outside of the original 10, the 1960s is the decade with the most amendments passed (though the 1860s doesn't tie on a technicality).

If your putting the polarization in the NO CURRENT EVENTS range, I can't really speak to it, but sixish amendments in living memory should at least put a question mark on the idea it's harder now.