The patent situation is broken in a ton of ways. Just think about the concept for a few minutes and you'll imagine many of the points.

As for the problem you're focusing on, the particular problem is that to actually your patent defensively (the original purpose), you must litigate. To litigate, you must have lawyers, and quite a bit of money. If the other side is capable of buying better lawyers, or lawyers for a longer time, you lose.