The problem is the quasi-monopolies (i.e. industries with very few players but very high barriers to entry)—but in the other direction.
I'm a Google Fiber user, but in this area, the moment that Google Fiber announced, the two other providers both suddenly rolled out gigabit fiber plans at around $70/mo. after years of charging about that for 5-20 megabit plans. Their customers all switched to the new plans while waiting for Google Fiber to build out (took many months) and as a result didn't go through the hassle of switching to Google Fiber once it was available, since they already had an affordable gigabit plan with their current provider.
Basically, Google encountered the power of monopolies in exactly the classic sense. They found out that it was very difficult to enter an existing monopoly-served market because the large interests are able to instantly match whatever the new kid on the blog was offering.
It also demonstrates the power of competition—as soon as *someone* was offering $70/month gigabit fiber, all players in the area were. But sadly, it is the new kid on the block that suffered most by incurring the costs of trying to enter at a lower price point without realizing the expected benefits.
As an aside, I also imagine that were, hypothetically, to pull out of this area, those gigabit fiber plans from the others would suddenly and magically "disappear" again.