In brief, I am looking for an example where Occam’s razor favoured a theory A over another theory B, but theory B turned out to be a better description of reality later. But let me formulate some criteria of what I mean by that:
First of all, as our modern perspective may be biased – e.g., due to didactical advances in the prevailing theory or new insights into historic experiments –, consider my criteria on qualities of theories to refer to historical scientific opinions and statements, as long as they can be considered to be based on reason (instead of, e.g., being strongly influenced by a religious bias).
At a given time, two theories (A and B) were comparably good at describing the same aspect of reality as it was observable at that time. They need not have been perfect descriptions of available observations, but they should not have been so far-off that they were applicable only to special cases or none at all.
Occam’s razor was reasonably invoked in a scientific dispute in favor of theory A. This invocation needs neither to have happened by name nor in a peer-reviewed publication (if such existed at that time at all). I am also interested in, but do not prefer, cases in which adherents of both theories invoked Occam’s razor (or similar) to argue against the respective other theory.
At a later time, theory B or a reasonably small modification thereof turned out to be a better description of reality than theory A. Alternatively, theory B is still used today for some aspects, while theory A isn’t. Theory B does not need to be the prevailing theory today.
I am asking out of curiosity. I am very well aware that the existence of such an example does not invalidate Occam’s razor.