"It's pretty hard to make out what's going to be a commercial success and what's not"

This quote by Gavin Rossdale speaks with the difficulty of anticipating what will be a commercial success as well as what will certainly not. It is frequently hard to determine what will certainly be prominent with the public as well as what will not. This is particularly true in the show business, where fads and tastes can change quickly. Rossdale is likely referring to his own experience in the songs industry, where he has seen firsthand how unforeseeable success can be. He is likely warning those who are aiming to get into the market that it is not always simple to anticipate what will certainly be a hit as well as what will not. Rossdale's quote is a suggestion that success is not always assured, which it is necessary to be prepared for the possibility of failing.