Theory is BS. U2's music was hardly conservative in the 1980s, it broke the mold and sounded nothing like everything else on the radio at the time. The U2 1st single that most inspired some WTF's???!! from the radio listening audience would be WOWY, not the Fly. With hair bands dominant, was it conservative or safe to go and release an album like UF? That is to say nothing of the fact that U2 vocally opposed Reagan's policies.
Others did a better job than me of explaining how AB was released under Bush Sr, ATYCLB under Clinton, etc. The lag time ensured that whoever's "culture" was still firmly in control during the recording process(1990 and 1999 for AB/ATYCLB, still firm Bush 41 and firm Clinton).
Now, as a political scientist, let me explain why the President has a very minimal influence on "culture." Elections are hardly ever the result of a complete change in how the country thinks. They are impulsive, going on the events and moods of the country at the time. Take the "Reagan revolution" for example. Supposedly started by the tax revolt out in CA- well that was not due to some liberal whacko raising taxes like crazy, it was rise in property taxes due to an economic phenemonon, inflation. It was a movement against a tax that is pretty much set, not by politicians, but by the value of your home. Plus, Reagan jacked the taxes he controlled big time in CA as well as when he was President. So why did he get elected if not for the cultural and social shift to more conservative values? 1.)the economy sucked, stagflation, oil crisis, etc mostly left over from Nixon's mess and dealt with prudently by Carter, but I digress 2.)Iran hostage crisis- combination of events that had been building in Iran since 1953 and the bad luck of Carter. He sends a rescue plane over, if it had worked, 99.999999% chance it would have, he would have been hailed as a hero, but the .0001% happened and the plane crashed. Combine that with Reagan's charisma and personal appeal and he wins. In the 81/83 recession, most Americans polled feared "Reaganomics" and the Democrats won big in 1982. 1984, again, Reagan is still charismatic, and the economy is finally rebounding due to the actions of a Carter appointed fed chairman, not Reagan. So what the hell, economy good, put the incumbent back in is how most Americans think. Clinton heralded no cultural/social shift at all- he won the most votes in a 3 way race, hardly a majority or a mandate at all, and then the economy was great in 96, so he wins again. I personally liked Clinton's policies alot better than Reagan's and think he had alot to do w/the economy while he was in office, but the point is, regardless of our views, most Americans in the middle who decide elections went for Reagan in 84 and Clinton in 96 on the strength of our economy. Bush heralded no cultural shift as he didnt win in 2000 and barely squeaked in 2004. Obama, not really, people just want someone honest, who will level with us, who is smart and humble and his mandate was big, but it was to fix the economy and restore US standing in the world, not bring about a massive cultural shift. This is not what Presidents do, culture is shaped by broad trends that develop over time.
Theory, in summary, is bullshit, someone has even more time on their hands than I do on this 4 day weekend!!