The "system's image" is important because the end to all patents or IP would be absolutely devastating to the U.S. economy, killing way more jobs than patent trolls do. The public needs to trust the patent system.
The question of which of those will have a larger impact on the economy, and for that matter which behavior we would prefer to see encouraged, remains open and does not have a well-known or accepted answer as you've implied.
I think you mean "companies who sue over patents", not "companies who get sued over patents"; the latter are not the ones looking to prevent copying.
I'd also point out that that issue doesn't apply to software patents, since copyright already handles that issue quite effectively for software.
> Without the possibility of recouping investment, new product development would slow
Standard patent rhetoric. The corresponding anti-patent rhetoric would be that without the issue of spurious patent lawsuits and workarounds, product development would accelerate. Both claims require evidence, not just assertion.
> Which in turn would harm companies that exist solely to copy other products
Because of course the world is divided solely into companies that love patents and companies that exist solely to copy other products.
There's a large ecosystem of innovative companies that treat patents as overhead and cost rather than value.
This is not actually surprising. A patent is a monopoly. A monopoly creates an environment where you can jack up the prices without improving the product you're selling and that's why americans pay much more money for pathetic broadband speeds than majority of other countries, while cable companies are comfortably profitable. It's also why a day after Google introduces 1GB broadband in one area, Comcast or TWN suddenly announce that they also will provide such speeds in this area (but not anywhere else).
Monopoly is what devastating to economy. Patents are monopoly and they are devastating to economy.
But once you max out the return from copying existing innovations, the only way to keep growing is to generate your own innovation. Then you want to protect those innovations. So the U.S., now one of the most innovative economies in the world, has strong IP laws and fights to protect them.
It's true: killing patents would most likely cause an immediate economic burst in the U.S. It would basically be a reduction in cost for many companies, who would realize a benefit in increased profits.
But over time, without patents, there would be reduced incentive to invest in capital-intensive innovations. That is why, despite the studies you cite, every major developed nation has strong protections for IP today. It is why major innovations like broadband, pharmaceuticals, electronics, software, etc. come out of nations with strong IP protections, not nations with weak IP protections