Huh, that shaft ended in loud screech and a clang... Let's drop another shaft!

Why don't you have to care about the infinity of theories?

I don't have to care about the infinity of theories because if they all make exactly the same predictions, I don't care that they are different.

This is highly convenient because I am, to quote an Agent, "only human" and humans are not well set up to deal with infinities.

they can be criticized as a group by pointing out that a shovel won't help solve the problem

How do you know that without examining the specific theories?

We can only act on solutions we know of, and I have a criticism of the shovel category of ideas as we currently understand it.

Right, but the point is that you do not have solution at the moment and there is an infinity of theories which propose potential shovel-ready solutions. You have no basis for rejecting them because "I don't know of a solution with a shovel" -- they are new to you solutions, that's the whole point.

To the extent you have a default, you can partly change what that default is, and partly reinterpret it after doing the observation.

Yes, of course, but you were claiming there are no such things as observations at all, merely some photons and such flying around. Being prone to errors is an entirely different question.

one entity (or none) is as good as another as long as the predictions come out the same?

Predictions do not come out of nowhere. They are made by models (= imperfect representations of reality) and "entity" is just a different word for a "model". If you don't have any entities, what exactly generates your predictions?