Maybe someone can answer this for me - what kind of money is there at the world championships?
Track and Field had this problem starting in the early 1990's - the best athletes started grumbling about not going to worlds. It didn't take long to institute big paydays and the best in the world started competing again.
Now, there are numerous differences between track and cycling on this, so it may not be the best comparision. But the takeaway is that at some point, it stopped mattering to athletes that it was "The Worlds" and the organizers had to give it some reason to matter again (in this case money). It's all well and good to say it's the worlds and it should matter, but if the athletes don't go, then it has to change.
All that said, I actually think the cycling worlds is pretty competitive and I'm not sure they need to change. I think it's the Americans in particular who are not going this year and I wouldn't change it just for Americans (we're weird not matter how you look at it). The cycling season can be pretty brutal and in this day and age, I would expect a handful of the top grand tour riders not to go to worlds as well.
In most sports, if you're one of the two or three best in the world at your sub-discipline, you have a chance of winning worlds. But in cycling, aside from the TT which is a very limited discipline (my favorite though), there's just one road race that has to serve as the worlds for Cavendish, Cunego and Contador alike. I'd argue that Cavendish and Contador pretty much couldn't win this year's worlds despite clearly being "the best". As such, you're always gonna see a number of the best riders not ride. Aside from Zabriskie in the TT, none of those Americans who are skipping really had a chance of being on the podium - Hincapie in his younger days maybe. maybe.
As an american, it's disappointing not to see mroe of the good guys there. as a cycling fan, I don't think their absence will have much impact aside from the inventor of Z-nuts.