1. The Citizens United ruling allows unbounded money to flow into campaigns.

2. Campaign funding determines election results.

3. Elected officials determine what America does in terms of law and regulation.

4. Billionaires pour tons of money into campaigns.

When you allow dollars to effectively determine elections instead of votes, the end result is oligarchy and the rule of the rich.

Here's an excerpt that starts to answer your question:

> The 1970s was a turning point in the other direction. In the decades leading up to the '70s, the government had grown increasingly aggressive—intervening in the free market to defend competition in more and more ways over time. Then a lawyer named Robert Bork completely transformed the way courts would interpret antitrust law. The approach to enforcement reversed direction away from protecting firms and toward a consumer focus, paving the way for today's tech giants.

The blame is scattered all over the place, but the main idea is that government has become increasingly technocratic; trusting industry leaders to tell us that their industries are too complicated for politicians to interfere in. This is not just a question of "regulation" -- the problem is bigger than regulation since anti-trust is generally not a regulatory issue so much as a law enforcement issue. Regulation is actually part of the problem to a degree, as regulating fewer larger entities is "easier" than regulating a diverse healthy industry.

In the 1970s, a combination of things -- Bork and the Chicago school's notion that "consumer protection" was the main objective of anti-trust action, Ralph Nader and the burgeoning consumer rights movement that joined forces with this (because of the regulatory pressure above), and the switch of the Democratic party from a populist party to principally a social justice party. All three of these had positive effects as well (prosecuting abusive monopolies, increasing customer safety and dropping consumer prices for goods, and advancing the civil rights movement), but between them they ended up dismantling the New Deal era protections against big businesses that led to the massive consolidations of the 80s and 90s across almost every sector.

There are many things that Stoller points to as positive things that I was dubious about but he makes a compelling case -- specifically pricing controls (where the manufacturer can set retail price ceilings and prevent discounting). Some of it has been things that I have had trouble specifically elucidating -- why it's bad that Disney controls both content production and distribution, and how Congress can wield (and has wielded, in the past) power directly.

Serious research with data, but also approachable for noneconomist.

Thankfully the pendulum has been swinging back in the other direction for various reasons like the fall of the USSR, realization of the dangers of regulatory capture, etc. But then we've been allowing all these horizontal mergers recently which just doesn't make any sense to me.