The only things that really seem to distinguish a great bowler are his/her speed and accuracy. That's basically it. There's no Michael Jordan running on thin air with his tongue out. There's no massive 7' Shaq shattering glass with the force of his dunks. There's no Peyton Manning watching over his team, radiating some austere strategic wisdom (barring this last Super Bowl...).
Frankly, I'd (very seriously) rather watch professional juggling than bowling.
Finally, the overall style of bowling as a sport is decidedly 1970s midwest America. The US is undergoing probably an unprecedented urban trend right now. As profoundly shallow as it might be, bowling is just not sexy at all.