Personally, I don't mind that they have outside ventures, it's probably a healthy escape and more productive than drinking and gambling. However, I don't understand the business sense it makes to own your own brand or clothing line when you're a footballer.
Football is tribal, if your own fans aren't going to buy your product, no one else is. Messi and Ronaldo almost transcend the tribal nature of football due to being perhaps the greatest footballers of all time but there are still fans out there who wouldn't be caught dead in a Messi or Ronaldo shirt due to club allegiances.
Zlatan's clothing line, that was just underwear, closed down last summer after losing £18m over two years. He's way more successful than the likes of Lingard, played all over the world and a god in Sweden, yet he can't shift clothes for love nor money.
You have to think that these guys are incredibly ill advised by shit agents seeing pound signs or their ego's are hugely inflated. Probably a mix of both...