World Cup is sanctioned by the NHL and all the best national teams is there. They even have the best players unlike several other international meetings. Canada Cup/World Cup has never had any kind of promotion or relegation and the need have not been there since it is invitational and the dynamics in the hockey world is like it is. There are the big six and during the years the other teams have been to weak. Missed that.
It is quite obvious why it is a joke. The best players are NOT playing unlike World Cup. World Championship was, unlike its name, more of a European Championship until the 70's when the best Swedish players left for playing in NHL. Then it has been a strange mixed thing that do not have much credibility in a sporting sense. But people still seem to like it, even though it is just a weird thing. EHT has lost more and more relevance during the years. Nonsense tournaments with D-grade players.
The best players not being there doesn't make it a gimmick. The Olympics wont have some of the best tennis players as they've declined to go.. does that make the Olympics a gimmick too?
A gimmick would be Team Rest of Europe or a U23 combined team of America and Canada.
You mention that they best national teams were there at the World Cup.. not true..
Canada didn't have all their available players (eg. Connor McDavid)
US didn't have all their available players (eg. Austn Matthews)
Swiss and Slovaks were not there at all
Canada has been in 5 of the last 6 World's finals.. definitely not a Euro Championship.
I thought the point of EHT was to try out different players and combos?