No, you can avoid a monopoly by going without it's services or products. You might end up either slightly inconvenienced, or living like a cave man, or dieing from some horrible disease because said monopoly makes some drug that you need to not die slowly and painfully, but you can avoid it.
Think "Matrix" with this. As long as you technically have a choice, it is all good and wholly acceptable. The second you don't, there are issues.
Of course, some of us live in the real world. Where "I can technically disassociate myself from these bastards" doesn't really work out to much of a choice.