You have no evidence whatsoever that more progress wouldn't have been made if people had believed deBB from the start. It's the same mathematics but a clearer conceptual picture, so I rather suspect there would have been.
(1) Occam: Just for the record, deBB adds no math that is not already there - everything follows from one semantic change in the meaning of the word 'probability'. It also eliminates the - to most people uncompelling - postulates about measurement (so it actually has
fewer premises..). It gives a completely new interpretation of quantum phenomena in which e.g. probability plays no fundamental role. The descriptive content is identical but the theories are not equivalent at all. There is no basis to apply Occam here.
(2) You can't moan about the theory being non-local unless you yourself can explain entanglement in a better way. And you can't - we already discussed this. In fact, I seem to recall you said
'I believe in nonlocality'.
(3) As for being contrived - OK, let's work this through. For a start, you're confusing Copenhagen with instrumentalism/shut-up-and-calculate.
Let's start with the equations of quantum mechanics (the Schroedinger equation, say). Here are three typical choices:
* Instrumentalism: assume that we can never know what the mathematical objects in the theory represent (or that we don't care) and just look at the probabilities of experimental results. Perfectly reasonable if you just want to build stuff.
* deBB: assume that the mathematical objects in the theory correspond to things that actually exist. This is also perfectly reasonable if you want to build stuff (it's the same maths) but it makes completely clear what is happening in an individual quantum event and hence guides thinking.
* TCI: because we are in thrall to the latest 1920s philosophical fashion which we heard in a pub assume that
one of the two mathematical objects in the theory corresponds to something (God knows what?) that exists er.. only when humans look at it, and insist (with no evidence whatsoever) that nature must be
fundamentally probabilistic. Allows you to build stuff but makes everyone who studies it utterly confused (witness the hordes of students posting here).
Now, if we asked a panel of independent witnesses to say which of those options is more contrived, what do you think they would say?
But who says metaphysics is not useful? Take the guy in the
https://www.physicsforums.com/showthread.php?t=372423" who's going on about the momentum being imaginary in classically-forbidden regions. His whole argument (though he won't have noticed this because he thinks philosophy is pointless) is based on the idea that an actual particle is tunneling through the barrier and that it has an actual momentum given by quantizing the expression '
mv'.
Now of course, if you do assume that particles exist (deBB) then their momentum is
not given by the quantum equivalent of
mv but by something else (because of the existence of the quantum force or particles being pushed around by the wave field). So the quantum-mechanical 'momentum' operator only gives the true momentum of a particle in the classical limit i.e. when the wave component is passive. Thus when you 'measure' the momentum in a quantum system, you are not in fact measuring
anything at all. This is what people mean by 'contextuality'. So when people make physical arguments about 'the uncertainty in the momentum' they always talk
as if they mean the actual uncertainty in the actual momentum of some particle even though, strictly speaking, \Delta p refers to one component of the stress tensor of the wave field.. (see Peter Holland's deBB textbook). Ho hum.
With hindsight we can now see how impractical, inhibiting ideas came to dominate and distort the entire development of quantum theory. The early quantum physicists attributed to nature a limitation we can now see was simply a deficiency of contemporary thought. [Holland, 1993]
