Indeed, I think theorists tend to make mistakes of either deductive or inductive bias. They start out tacitly assuming that reality must be some slightly noisy instantiation of a mathematical theorem ... that their favorite equations are logically true and for some mucky reason or another we just observe them as being noisily true.

From the post above:

To assign more than 50% probability to the correct candidate from a pool of 100,000,000 possible hypotheses, you need at least 27 bits of evidence (or thereabouts).

... or you just need to be that one guy who made a wild and unjustified guess about where to assign more than 50 % of the probability (despite not having bits of evidence to support it) and then be lucky.

This is true even if you call your guess a "hunch" or "intuition".

Only if you make the further assumption that whatever process that generates hunches or intuition must be decision-theoretic. That may not be a bad assumption, but I'm not convinced it's accurate in human beings. From my own readings about Einstein, I think it's more likely that he over-asserted the relevance of differential geometry and justified the pursuit of a theory along those lines with what is essentially faith in the mathematics. I don't think it was a subconscious extension of integrated evidence at all. For every Einstein whose hunch focused on the right general field of mathematics, there were probably dozens or hundreds of other physicists who just thought that burgeoning algebraic topology was the ticket, or perhaps non-standard analysis was the ticket, or perhaps representation theory was the ticket.

Many theories have been defended on grounds of beauty - and been wrong. Heliocentrism was an elegant theory that worked well and explained many things like the absence of naked-eye precession. Just before Einstein, we can find examples:

According to the vortex atomic theory originally proposed by William Thomson in 1867, atoms were nothing but vortical structures in the continuous ether. In this sense the atoms were quasi-material rather than material bodies. As the ultimate and irreducible quality of nature, the ether could exist without matter, but matter could not exist without the ether....By the early 1890s the vortex atomic theory had run out of steam and was abandoned by most researchers as a realistic theory of the constitution of matter. It was never unambiguously proved wrong by experiment, but after twenty years of work it degenerated into mathematics, failing to deliver what it promised of physical results. Physicists simply lost confidence in the theory. On the other hand, although the vortex atom was no longer considered a useful concept in explaining physical phenomena, heuristically and as a mental picture it lived on. Wrong as it was, to many British physicists it remained a methodological guiding principle, the ideal of what a future unified theory of matter and ether should look like. According to Michelson, writing in 1903, it “ought to be true even if it is not” (Kragh 2002: 80).

--"A Sense of Crisis: Physics in the fin-de-siècle Era"