Some teams during a best-on-best tournament don't even have 90% of their players due to injuries or personal circumstances... I mean you lose 3 out of your top 23 players and you're no longer at 90% available
The WHCs aren't that bad, most of the players in the tournament are NHLers and sometimes top nations get a few "A" team players, or even an entire unit could almost be the same as it would be in a best on best tournament, as Sweden's defensemen at the 2018 WHCs nearly were (which in no small part lead to their gold medal). Very, very few people in Canada cared about the World Cup in 2016; NHL fans I knew didn't know it happened and when they learned of the format, completely dismissed it.
Measuring how much Canadians care about international tournaments, my observations have been:
1. Olympics
2. WJCs
3. Proper World Cup without gimmicks
**massive gap**
4. WHCs (thanks in part to annual TSN coverage and promotion)
5. Olympic hockey without NHL players
6. Gimmick'd World Cup
7. U18 WJCs
8. Spengler Cup