This year, off the top of my head, in the US, Marley & Brubaker, even if they finished high enough at Nationals to qualify for 4CC'S or Worlds, couldn't go this year.
In past years, the following new teams won medals and would not have been able to go to Worlds or 4CC's without taking a trip to Europe first, wasting money they probably did not have since they were new teams (usually the 4th place couple gets a 4CC's berth since at least one of the top 3 won't go:
Weaver & Poje
Silverstein & Meara
Steigler & Magerovski (debuted in 4th)
Navarro & Bommentre (debuted in 4th)
Gregory & Petukhov
Semanick & Kravette
Semanick & Gregory
Blumberg & Siebert finished 3rd in their first year at US championships, if one is to believe wikipedia
Rene Roca and James Yorke finished 4th in their debut year, and if there had been 4CC's then, couldn't have gone.
Probably there are others; I just don't remember them.