Most of us on here work in software - how many times have we seen tech companies get their products and services deep inside an organization and milk it for years once they have leverage. Once it gets too bad, alternatives begin to come in to the marketplace. These are usually cheaper/better.
But still the practice happens over and over again. This means that those years of milking it is worth it.
But due to collusion, sometime-insufficient regulation (e.g., ad networks that can and do deliver malware), sometime-overbearing regulation (e.g., software patents), and ... well ... the rest of the real world, Adam Smith market economics is exceedingly reductionist. It works in the microcosm. Until you take into account that no economic entity or system is fully enclosed.
For example: has Blackboard yet been toppled, or are they still suing and/or acquiring any potential competitor via its vast patent portfolio, all the while being the absolute worst solution to its problem possible?
I wonder if we could create a simple little Web site people could post markets with virtual monopolies that that would like to see disrupted. It could act as an ideas board for entrepreneurs looking for fertile start-up areas.
It could be a simple post, but with the opportunity to flesh it out out with information on barriers to entry etc,potential market size etc.
You could post about blackboard. I could post about TES.com/jobs which has a virtual monopoly on advertising jobs in the UK teachers market, despite appalling service and ludicrous prices.