The real problem for them is not actually PACE, though that it is what will bring them down.
The real problem for them, the thing that is really going to finish them off, is that they went in way too hard, way too early, starting back in the late 80s, long before their hypothesis had been tested properly, or even tested at all.
PACE, the "definitive" test of that hypothesis, was only set in motion around the mid-2000s,
about 15 years after they first started making their bold unambiguous claim, and started ruthlessly and effectively inserting it into the core of clinical, educational, media, and policy advice at every opportunity. Furthermore, PACE did not start reporting outcomes until 2011, which extends the lack of results from adequate hypothesis testing out to nearly 25 years.
They also used ME/CFS/FM, etc, as a Trojan horse to widen their claim to cover all of society, and encouraged it to be used by government and commercial interests to justify some very dodgy and nasty policies and practices indeed, that not only continue to this day, but are
rapidly getting worse (and exactly the same thing is now happening in Australia, a straight copy of how the UK has been doing it).
From the start they were absolutely sure that they were right, and that the evidence would eventually catch up and confirm their hypothesis, and make heroes of them.
The evidence caught up alright, but it didn't confirm it. Indeed, the evidence is increasingly disproving it.
And all along the way there were patients, and others, clearly pointing out the problems with their approach, and warning of the consequences. But they just kept doubling down and charging on even harder and blinder.
All this is on the formal and informal public record.
They, and their enablers and clients, are going to have to answer for it. Sooner is better.