As long as the patent is for some actual innovation, there is nothing wrong with this market structure, economically or morally.
Why? Ideas are cheap, execution is everything and all that. You don't have to literally be the person executing on it, but whoever you transfer or sell the patent to should. I'd be ok with licensing or selling patents to others to build the technology, I'm not ok with licensing or selling the patent to others who will only use it to sue people who do try to build something similar.
The concept of patents was to encourage innovation, not stifle it.
Its also quite common that multiple people invent the same thing at roughly the same time. With these patent trolls, if one of these people gets the invention patented first, but does nothing but rent seeking with it, that will prevent others who came up with the same thing but were too slow to patent it to even try.
Couple that with overly broad, vague or downright invalid patents and you end up with a system that discourages, hinders or puts a large cost on actual innovation. Even if a patent is provably invalid, it costs money in legal fees to get it overturned.
Without the ability to sue people infringing on your patent, how do you ensure people will pay to license it?
Let's say you have a patent. You're trying to get someone to license it. They decide, no, we'd rather just use it for free instead. Now you have no buyers, and no licensors -- what is your option but a lawsuit?
But honestly, I'd be happier to just abolish patents altogether.
A research program that only produces patents for patent trolls seems like a useless research program.
I wholeheartedly agree with the sentiment that you need to actively use the patent in a product or forfeit all protection.
The alternative: grant a patent but if it not used within some scope of time in some way it becomes public domain or otherwise no longer considered a person's intellectual property. So you go to some company and say "I've solved your problem and I want to license my solution to you" and they tell you either you're going to sell it to them cheap or they'll just wait you out. You either take it or lose the patent in short order and now they can use it free. Now the only people that even own intellectual property are the big guys, and if you don't sell they let you lay fallow until your ownership becomes forfeit. You either sell to them or lose the patent.
I hate patent trolls too, but this alternative is worse. I personally don't like intellectual property in general, I think the best solution is to just not have it. Trade secrets are one thing, making it illegal for someone to reverse engineer something they bought or draw pictures they saw elsewhere in public is a bit absurd.
Take James Watt for example, Matthew Boulton could just have told Watt to take a hike and started manufacturing improved steam engines by himself. Watt couldn't have afforded to make steam engines independently, and why would any investor bother supporting him with capital if they could just set up production without him too?
The problem is with trivial patents, not patents in general.
Watts held back progress significantly and steam engine development was hampered by his and others patents until the expired. The steam engine would have been built to pump water out of mines whether patents existed or not.
You have transformed a structure where one entities invents and produces to a market structure with one where those are separate roles.
You like the former and abhor the later. But from the outside, this change is absolutely meaningless. It's no different than any other make-or-buy decision.
(Note that "sells a license" is exactly the same as "patent trolling".)
All these feelings you people have are based on the idea of "superficial" patents that aren't "real innovation". Which is, indeed, a problem. But it has nothing to do with the above. Assume some actually useful patent, and these objections fall apart.
Will it? Or will we have to wait for the patent period to expire of said technologies.