To be honest, I don't think that's the big issue with patents. If you're patenting a specific method for doing something, then either that method works (in which case, it shouldn't matter whether you have a working prototype) or it doesn't (in which case, there's no real harm in patenting it because the implementation is useless).
Just to give a whacky example, if I come up with a design for a new kind of nuclear reactor that should theoretically work, I think it's fine that I can patent it even if I don't have the resources and nuclear material to build it. If the design works, I deserve the patent for coming up with it. If the design doesn't work, then it doesn't really matter if I have a patent, because nobody is going to be implementing that design.
Or even if you disagree with that, I would still argue that this kind of situation isn't what's causing problems.
It seems to me that the issue with patents that is causing real problems is that patents are granted for things that shouldn't be patentable. You should only be able to patent specific methods and implementations, and not general ideas. So for example, patenting an bezel-free display should not be possible. In order to patent something like that, it should have to be a very specific design of how the screen would function without a bezel, or a specific manufacturing method. That method or implementation should also be novel and non-obvious. So if the design is very much the same as a design that existed before, you shouldn't be able to patent it. If the design is basically the first thing an engineer would come up with when trying to create a bezel-free display, then you should not be able to patent it.
It seems to me that those rules are already on the books, but they're just not being enforced. I'm not sure if it's because the patent office is corrupt, or the people granting the patents don't understand technology well enough, or because they just don't have the resources to review patents well enough. It seems like a lot of silly patents are slipping through, though.