"Since We Can't Eliminate Them"? The idea that some arbitrary made-up rules can't be eliminated is simply absurd. Sure there would be strong resistance from the powerful monopolies that have been built on the current patent system, but that will be true for any proposed change that threatens that power. If "we" refers not to humanity but rather to those of us who are not politicians or lobbyists willing to bribe politicians then I concede the truth of the statement, however that same logic also applies to the changes that RMS proposes.
Any change that threatens the existing monopolies will be a huge battle to pass, and proposals that attempt to adjust the balance based on utilitarian arguments tend to be decided based on "favors" (i.e. the largest bribe, although it may not be monetary). Although I feel that the utilitarian arguments against software patents strongly outweigh those in favor of them, that matters not to politicians as long as there exists some utilitarian argument that they can point to in order to justify their position. They only need enough justification for a soundbite, not a rigorous debate. Therefore a change like the one proposed by RMS seems unlikely to be successful.
There is another way forward, and that is to embrace the moral arguments to eliminate patents altogether. It may seem crazy; if ending software patents is so difficult, eliminating all patents would seem to be much more difficult. However, moral arguments trump utilitarian arguments. Politicians cannot effectively counter a moral argument by simply pointing at a utilitarian argument. It is simply wrong to make a person legally liable for using their own property in a manner that they would have no reasonable way of knowing infringes on the so-called "rights" of others. Of course there is much more to the moral arguments, but this doesn't seem like the right forum for that discussion so I will leave it at that.
The problem is especially acute for software because ideas are developed so quickly in software, but I find it to be shortsighted to be focusing on a software-only solution.