i think a lot of the hype some players receive is due to entities like espn. they have a tendency to highlight certain players in certain sports - griffey jr., jordan, kobe, shaq, lebron, Tiger, brady, judge, harper, etc. Those guys were/are always visible on espn, and espn is a network that probably every cable and satellite subscriber has. the same can't be said for MLB channel, or the NHL network, or the Golf Channel.
i think we can all agree that MLB could do a better job of marketing itself. The NBA and NFL have done a lot more nationally than baseball has in this dept.
As for Trout, I saw an ad for a baseball video game last night, and it was all about him. I still think he should do an endorsement deal with Jersey Mike's.