Appeal vs participants vs appeal to TV audiences is indeed the crisis it seems we're looking at. "Gravel is growing, what if we got in the road stars, maybe it'll blow up". And maybe the huge popularity of Strade Bianche also plays a role.
For me the big question is what the model should be of top level gravel races. Is a certain degree of overlap with the road peloton desired?
I can definitely see full time gravel riders get mad at this event suddenly being 'their' WC with 3rd rate roadies being able to win without even much of a contest.
Using road riders is a fast and lazy way of engaging occasional audience, instead of building up slowly the awareness to the guys that usually compete in each variant.
Athletics has space to promote itselfs with athletes from different specialities. We have Bolt, Duplantis, Kipchoge, Isinbaeva, Warholm, Radcliffe, etc. But in cycling it seems that only the road riders are sufficiently well known to make it viable to market the events. In XC, how many mainstream praise has Schurter or Absalon generated among the years compared to the hype generated by Pidcock being able to be a MTB world champion while being top-10 material at road events and cross world champion?
Putting it in absurd terms, this is like an athletics federation who focused on track events, due to the rising popularity of road running, start organising road championships consisting of 400m road runs with the jamaican sprinters at the start due to being more known.