Reagan destroyed the middleclass, which led to Trump's barbarism.

And it was conservative reactionaryism and the Christo-fascist right empowered by Reagan that killed progressivism as a mainstream political movement – conservative reactionaryism that sought to compel conformity and punish dissent, diversity, inclusion, and expressions of individual liberty.

Conservativism embraced racism, bigotry, and hate, fear, ignorance, and lies to facilitate Republican political success resulting in the Trump malignancy.

The forces of conflict during the Vietnam War, while breaking, in some fashion, the establishment, the vacuum that followed led to what we see now as the last chances for the middle class.
The article expresses the challenges unmet by the highbrow. The middlebrow grew from the success of the GI Bill and the money game became the adman's dream.
Tearing things down, the rebellion of the 60's, was emotional. There was no plan to rebuild.
Ideological George McGovern was crushed and erased. The hole had been paved over.

What was torn down in the 60s?

The Civil Rights Act broke down doors in schools, voting booths and employment. The women's movement gained momentum that allowed for an independence with rights that had been exclusionary. Like credit. Birth control, the Pill, created a sexual revolution. The draft, was challenged and eventually cancelled.
The protests against the establishment opened doors in myriad ways.
The button downed mind of what was, was upended by the children of the generation that grew up in the depression and fought the fascists.

Wow. Civil Rights, Women's rights means "tearing down?"

Overcoming barriers to people's full life expression is building up, not tearing down.

restriction as the point. The rights of blacks, immigrants, women, LGBTQ, divorcees and the like, were restricted by the white supremacists that are trying to take back the country.
All people want to live free of restrictions forced on them. It is still a fight to keep them from being reimposed.

It is the white nationalists, the Nixonites and Reaganites, the misogynists who led to Trump, not the Freedom Riders, not the Women's Liberation advocates, not the antiwar protestors, not the LBGTQ activists, not the "hippies."

American as all of us. We have not been able to educate nor mold them into socially accepting our openness to all of mankind.
They are now fighting tooth and nail to hold onto the gains they have made with trump.
Woe to us having been unable to stop him and his minions.

and paying attention for decades, I tend to agree with your assessment more than the articles.
The Reagan revolution bent this country into the shape we are in now.

like ALEC, the American Legislative Exchange Council. Much of that funded by RW billionaires who wanted to reduce their own taxes and destroy the social safery net created by liberals.

Popular culture is not the threat, and in fact popular music has always helped movements for social justice.

Snobbery by the elites will turn people against them, but that's been true throughout history.

The decline in classical music sales compared to popular music is mostly because it does not have large numbers of new composers creating new classical music. Classical music fans, once they have recordings of favorite symphonies by the great classical composers, are not going to be buying new recordings of classical music very often. Not unless audio technology improves, anyway, when they might replace all or most of their collection with the latest type of recording.