Considering we can implement and simulate a Turing machine and get actual calculations, how do you consider them to be completely abstract/theoretical?
A Turing machine is not a real device; I suggest reading the Wikipedia article on abstract machines [0], which says verbatim: "Turing machines, for example, are some of the most fundamental abstract machines in computer science."
Abstract/theoretical doesn't mean "doesn't do anything practical". Labeling gravity as a "theory" doesn't mean that it doesn't hold things to the surface of the Earth. The Turing machine is a model of computation that is so simple (so abstract) that we can implement it with a pencil and paper very easily, and it can be used for actual calculation, but it is not — and never was — a literal device that existed physically.
