Overview of the patent system:
The patent covers an invention, and the patent applicant can get monopoly of the use of the invention for a limited time. He can then force others to not use the invention or license it, of his own choosing.
No. That is almost as bad as claiming that since there are police, there is no crime.
A patent doesn't do what you described here very well, that would give the law magical powers that it doesn't have. Patents are routinely violated, they never result in monopoly. What they do is provide an offensive legal weapon to point at those that attempt to do something like what you have patented.
Using a patent is an expensive proposition, and may not succeed, so you aren't going to enforce it unless the perp is rich. Win or lose you have to pay. Lose really badly and you have to pay for the other guy's legal costs too. If you do ultimately win your patent defense case, you aren't done. All you get is the court sending you to another case to figure out what the "reasonable license fee" is, and that's what you get. If you win a good award, then you have to try to collect it.
Do you know how many patents get profitably violated? All the good ones.