A brand can have all of the floor space they want - for it to move, it has to be a good product. You then have to convince the staff it's a good product, who would then have to convince the customer it's genuinely a good product. And in my experience, where I worked for a retailer that gave EVERY BRAND a chance (hell, they booked BROOKLYNITE, long live TH) that's where the disconnect happens.
Note that most of your sales staff are young and really don't have a vested interest in the health of the business, let alone servicing the customer properly in some cases. And their sales pitch is almost always going to be an evangelized one. If the product can't win over the staff based on merit, the only way your staff would push that product is if they SPIFF the hell out of it - and customers will sense that a mile away. Plus it doesn't help when customers walk in with the feeling that they are more informed than the staff is - and the way that I was able to combat that was to be able to answer all of their questions and concerns truthfully.