I think #1 is by far the biggest reason (in addition to cost of playing, as well as the already-crowded US sports calendar). Was hockey really more popular in the US a.) before Europeans joined the league (ie, players had "pronounceable" names) or b.) when scoring was higher? Are there attendance or TV figures to back this up? Were ESPN's ratings great during the golden years of 92-94, then cratered during the late 90s?
While I certainly want a return to the more wide-open play of 91-94 (or even 05-10), I don't think it influences TV ratings much. Local markets are king. IMO the one and only thing that could lift hockey out of its niche status in the US is a super-charismatic American player with a Gretzky/Lemieux-level skillset.

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