Asymmetry of information is what got you to the top. You know more than your competition, more on a productive process, on consumer behavior, on business partners, on leveraging financial avenues, on political "contributions", on questionable use of insider information, etc.
And Information is what keeps you at the top: knowing who to "lobby" to create convenient regulation that hurts your competition the most, is the most effective way monopolies use to stay that way.
Monopolies are not monopolies in the abstract, they have to fight everyday to keep being a monopoly and they do that by leveraging information asymmetry.
It’s not simply asymmetry of information though. Monopolies often have an incredible amount of financial power that they deploy against people trying to enter their market. Or maybe a company is on top because of their execution. I really don’t think the entire phenomenon can be explained by information asymmetry.
You would have to establish that no one else knew who to lobby, which is far from clear. Also I know exactly who to lobby for certain things I need from the city, but that clearly isn’t enough, because my lobbying efforts have failed miserably.
The asymmetry is in more than one area, those where only examples, and they probably have an asymmetric advantage over you in all areas.
That is why, even if you know who to lobby you can't get a meeting, but they meet everyday. You don't know who to bribe to get a meeting. And on and on.
Dominant market power is maintained by having control of information in a market. Google has control on the information about advertising and user searches that competitors don't. Amazon uses comprehensive sales data that others don't. Apple uses its power to enforce ignorance of competition to its customers.
You can only get dominant market power with an asymmetry of information (about how to produce whatever thing it is that gets you dominant market power). This is why we have IP laws...
The at&t monopoly obtained power via government grant. There are many others. We have IP laws to avoid monopolies among other reasons, but they aren’t the only way to get monopoly power.
