You're also dealing with the nation's sporting culture. Football started as a college sport, and college football sank its roots into our sports culture long before the NFL became a monolith. Basketball started as a college sport, and college basketball mattered long before anybody much cared about the NBA, and they have that great tournament.
But for over 100 years, baseball = pro in most people's minds. Get away from MLB and the first place people look is not college ball but minor-league ball. The aluminum-bat thing hasn't helped in that regard. Kids hit with metal. Grownups hit with wood.
The flip side of that argument is that broadcast saturation can drive demand. ESPN largely decides what people are interested in through their programming, as does FSN. Why do people watch events like poker, eating contests and world's strongest man? Because they are on.
But they only show those things when there's nothing else better to show. College baseball competes against late-season college basketball (talk about oversaturation) and as soon as March Madness is over, it's Opening Day, and everyone's carrying MLB. There's no window open for college baseball to rise to the top and get some attention.
The College World Series is great, but it's about the only time of year people pay attention to college baseball if they aren't a fan of a specific college baseball team.