Quantum tunneling is real. It is a major issue in the design of modern microchips because at a sufficiently small feature size, electrons start jumping nonconductive barriers and mess up the state of the chip. Intel had to resort to using high-k materials to combat the problem.
If it didn’t work and current QM didn’t give useful “predictive results” how are we pounding on the computer arguing about it?
and of course quantum mechanics can at a later day be subsumed into a new theory that says “hidden variables” (or something!) are right after all. I won’t hold my breath but I guess it could happen.
That’s what science does, new data ,new explanations or theories. The past theory becomes a part of the new theory. Maybe an integral part & maybe be relegated to an obscure creaky corner. (and even if its a part of the bigger theory it may remain useful for human-scale engineering purposes!)
If you don’t do that you’re doing dogma not science.
There’s people taking pot shots at QM. Here are some!
So far they have missed!
https://en.wikipedia.org/wiki/Hidden-variable_theory#Bell’s_theorem