Okay that's the idea, but do they do that today? It seems that today the more common story is: "big guy" patents everything under the sun before the fact and locks it away in a drawer, while "little guy" actually builds the thing and tries to sell it but gets crushed in the process. Or at least that's the one I hear told more often, maybe it really is the case that patents are promoting innovation. But we can't just assume it's working out like we thought it would.
That's the story we hear often with software patents, but those are relatively new. There's a long history of patents for physical things which may be less obviously detrimental.
FWIW, if I remember correctly, the reason we can even have software patents is because a hedge fund ended up trying to patent their process for categorizing or rating investments, and in their drive to patent a process as opposed to a mechanism, new law was decided. I'm being vague because I don't remember the details enough to be authoritative and don't have the time to look them up, but someone else might be prompted to.
To me, I can see a benefit to physical and software patents both, but I think they have very different effects and should be handled differently. If software patents were genuinely harder to get because they had to actually be complex and novel, and also only lasted 5-10 years, I don't think we'd really have much of a problem. I don't know how to raise the bar on their complexity in a good way though.