Is it truly surprising? For one thing the majority of people who watch the Worlds are 2 weeks hockey fans, who watch it because it has become an integral part of the country's culture over the years. For the other 50 weeks of the year these people have different interests. Then you have to consider that it is a) much easier to watch games for free in front of your TV than going to the rink (where you feel like the roof will fall on your head in some cities) and pay for that and what you get to see is on a much lower level than the Worlds, because even most of the weakest teams at the Worlds have players from better leageus than the Extraliga.
But perhaps the biggest difference is in the hype machine I mentioned in my previous post. When the time for the Worlds to be played comes around all the mainstream media are full of information, articles and reports about the tournament, whether we're talking about print, radio or TV and all the shops start selling stuff like jerseys, shirts, scarfs, Coca Colas with pictures of players.
With the Extraliga all you get is regular reports about the scores/rankings and some small reports, whatever else is published about the Extraliga it's 99% negative.
You can't live (or just visit) Slovakia during the Worlds and not realise that the Worlds are played. You can easily live here and never know that the top league is currently called Tipsport Extraliga, I doubt that most Slovaks could even name all the teams that played in the league this year, yet alone the players on these teams. Most people here would probably know that Gaborik played for Slovakia at this years' Worlds, I doubt anywhere near as many people would know that Stumpel played in Nitra and Handzus in Banska Bystrica this season.