My two cents is that Tudor's positioning and branding within the Rolex family is one of the issues driving the problem.
When Tudor first started, I think Tudor was the brand that essentially used excess Rolex parts an made watches at a lower price point (I could be wrong here, but I thought they were watches that essentially took Rolex parts and made different watches).
In a strange way, with that mandate, Tudor was free to make wild and wacky designs so long as the parts and internals didn't really require a lot of R&D or sourcing.
However, being wild and wacky to an extent can be hit or miss, and for awhile in the US at least, it was mostly miss. So Tudor disappeared and went into the background and regrouped.
Tudor then rebranded as the "Rolex before it became Rolex" brand. It looked into the archives and made variations on historically based designs. So, it seemed to me, Tudor became the brand for those nostalgic of Rolex past designs, but more importantly, Rolex prices of the past and availability of the past.
This was hugely successful.....for awhile.
But perhaps, this is a one trick pony. Yes, there are the Pelagos line, but largely, it's been the BB company, and I see the BB as a look into the past for Rolex.
Maybe people are getting bored of this aesthetic and have, or are, moving on.
It's a fine, and perhaps unfair, line the walk. I guess you do need a bread and butter line. Lord knows Rolex is the king and champion of luxury watches because of that. However, for all other companies other than Rolex, you do need to take risks and expand the line. Some will hit. Some will miss, and that's the risk.
Maybe Tudor adopted the safe approach too much over the past year. I dunno.