Peter, let me throw in some info and experience, accumulated through working with the MDR and supporting published standards (including the 601 family), in the last few years.
As noted above, the current list of standards harmonized under the MDR is indeed short. I'm not closely involved in the politics around it (and there are plenty, as I hear), and not EU based, so no inside info here... However, it's officially documented that the lag in getting a proper harmonized standards list stemmed initially from some deep disagreements between the EU commission and CEN/CENELEC. This was not specific to 601, not at all; and it cost us in almost a year of delay. The initial harmonization "mandate" drafted by the commission got rejected by CEN/CENELEC, and it took about a year to draft a new one (that had better chances of being accepted) and then get it through the legal pipework to an approved status. This is M/575, which can now be relied on as reflecting the future full list of standards that will be harmonized under the MDR (not 100%, obviously, but some close figure - my guess).
The last list harmonized under MDD is a good starting point for SotA arguments, but it has no official or semi-official standing for MDR - AFAIK. Obviously, as time goes by it becomes less and less relevant as representing the SotA. It's mostly a last resort. I think that M/575 is a better reference, and it's also more current.
The latest from MDCG on harmonized standards, that I'm aware of, is MDCG 2021-5. But this is more of a general guidance on working with published standards in the MDR certification process, and as far as I remember it doesn't shed any more light on the delays/politics around the actual harmonized standards list.
The useful bit is the clarification of the expectation to establish/justify that a published version that is used is actually SotA; and that publication of a new version doesn't automatically push the SotA to align with that version (sometimes this is the crux of the debate - there is disagreement about some elements in a new version that "violate" or "exceed" the SotA, and might need to either "mature" into that status or be dialed back).
Any specific nuances or battles around 601 are unknown to me (not my expertise), but from knowing the big picture I can assure you that the delay / political war around MDR standards harmonization extends far beyond any technical disputes around 601. I'm not aware of "the EU system" having a specific issue with, for example, the particulars being flawed. I'm sure that the system is aware of the fact that they are, and would have preferred them fixed sooner rather than later, but I'm not aware of a sweeping change in approach, in that regard, from the good old MDD days... More likely everyone is happy to keep the status quo of "let's do our best in writing up standards, well knowing they are going to be initially flawed no matter what, gather experience in the certification process and in the field, and hopefully come up with a better version in the next 5-10 years... Hopefully not too many people will die in the process!..."
The adoption of standards as EN and reaching agreement on Z annexes are nothing but trivial, for an array or reasons that are not always accessible to us mortals.
Cheers,
Ronen
