The problem is not the over-emphasis on creating, it's the emphasis on marketing.
There is nothing wrong with creating new magic. Many people, including myself, find it very enjoyable, and the sense of satisfaction gained from performing your own effects and routines to great success is so much better than nailing a carbon copy of somebody else's.
Creating is also a great way of learning how various aspects of magic have developed. As you create, you eventually find that many of the things you have seemingly come up with yourself have been done before. This is great when it happens, because you are put at an immediate advantage. Not only have you gained a much better understanding of the sleight/effect, but you now also have refined sources of information and teaching to help progress faster.
Discourage creativity would only have a negative impact on magic.
Marketing is the real problem. How many times have you seen a thread on a forum entitled "My new effect"? The word "new" in this title could mean one of two things. Firstly, it could mean that it is new (or coming soon) to the market, but this is rarely the case, and when it is, sadly, the second meaning of the word "new" also applies. This second meaning is that they have only just come up with the idea, in which case they should not be calling it an effect, they should be calling it an idea, and the only reason it should be shared is to get feedback and help in turning it into a working effect (although even that should come after some sort of development and work on the part of the creator).
Due to it's relevance, I thought I would share this. I love creating magic; it is cheap, fun, and can be very satisfying. A lot of what I perform is my own, and I have shared a few videos and ideas on magic forums before. I have now come to realise that overall, there is no benefit to doing this. It's nice to receive good feedback, but when you start receiving comments such as "Sell this now, I want to buy it!", it can often take a strong mind not to get drawn into the hype of your own effects. Public forums are also a great place to showcase your creations or ideas to people who want to steal from you. Because you give no method, some people can be convinced that if they ultimately use what to provided to create the same effect, then they have the right to call themselves the creator, because you never told them the method. There are so many people using the internet that even the tiniest minority of people like this could jeopardise your rights as the creator. If you want useful feedback and help with things you are developing, look to your most trusted friends, and find people with good experience and an excellent reputation among other magicians.
"Submit a trick. Invent. Be famous."
I'm sure you've seen this kind of thing before. This right here is a big part of the problem. Firstly, it hides the real benefit to creating. Inventing becomes about being famous, rather than being able to do something magical. Secondly, it promotes the creation of magic specifically for marketing. If we really want to create good magic, we shouldn't need any kind of motivation from other magicians or companies, the motivation should be in what you can do for the people you perform to.
Huruey