I suppose a tax loophole is nothing more then a clever application of the law, right?
So, forget about tax laws, take a simple example traffic rules.

Well, then I'm filing a patent for stopping at a red light: everyone that stops at a red light must pay me 1$.

This is exactly the same as a patent on a tax loophole: the application of laws.
You must pay the patent holder for using a specific tax loophole, which is just an application of the law.
Now I'm making you all paying for applying another law.

Patents are hilarious and disastrous.

There can be several reasons why a product doesn't sell.
One of the possible reasons is that the product in question is crap.
In that case the manufacturer will have learned all there is to learn from their screw-up in a very short time. It is then no problem that the product gets pulled rather soon.

A second possibility is that the competition is better and/or cheaper. Also in that case the manufacturer can take their expensive/under-performing product rapidly off the market.

But in many cases the reason that a product doesn't not sell immediately is simply that the consumers don't know it exists. Established names like Apple, and Microsoft can bring out a product and even get coverage on the evening news. Others simply don't get that exposure to the masses. Then it is normal that a product doesn't take of immediately.
The problem is that while a product is on the shelf, competing products are coming out. Since they are newer, there is a large possibility that they will be better or cheaper, pushing the "old" product towards one of the categories described above...

Does this study include the cost of the surface area (land) needed to put up a solar plant of industrial sizing?

Maybe NC has enough free space, but there are regions on this globe that are in high demand of energy, but where there simply is not enough space (at affordable price) to build such a power plant.