I'm going to take exception with this, because I see and hear similar statements a lot, as it applies to photography, guitars, and other tools of various trades. The exception I take has less to do with the spirit of the statement as it does with the finite nature of the separation of user and equipment. Let me explain as I dissect this into two perspectives.
Better (different) equipment alone does not make a photographer good, or bad. I think this is the sentiment of the original post, and if so, I agree with it. A photographer's skills first and foremost are built upon the way they see the world through the viewfinder, even when they have no camera in hand. That vision is then interpreted through their knowledge of how to interpret what they see through the optics they have at their disposal. Can you look at something and see it in 18mm, 35mm, 50mm, 85mm and 200mm? Do you know the difference that choice will make in how the image is perceived from the aspect of depth of field, composition of objects in the photo? If you're still letting the equipment drive you and not the other way around then giving you a new piece of equipment will not improve you one bit, though it may change what you produce.
Better equipment prompts you to be better. While the change is not instantaneous, I posit that giving someone who is reasonably skilled in their art and who has a penchant for learning a better piece of equipment and there will be a quick and noticeable improvement in their "performance". I've played guitar since I was a kid. Usually through relatively inexpensive amplifiers. They sounded good, and I thought I sounded good through them. One day I was in a shop and a friend encouraged me to plug into something different, hand made by a small company. The difference I heard was immediate. But it wasn't just that you could hear the improvement in the quality of the sound, but you could also hear the flaws in my technique that the lesser equipment masked. Money was laid down and the "wood-shedding" commenced. I experienced the exact same thing when I got my D600. The better equipment immediately showed me aspects of my photography that were lacking precision. And the bigger sensor turned on a switch in my head that harkened back to my days shooting film where what I saw with my eye once again began to line up with what I could frame in the camera. The better equipment has made me a better photographer. Not a great one. Heck, not even a "really good" one. But it was a course correction I needed on my road to where I want to be.
All that said, the key here is the motivation, work ethic and, let's face it, the innate talent of the person holding the equipment. It's the silk purse out of a sow's ear analogy. But I'll never tell someone that better equipment won't make them a better photographer until I first ask them if they honestly believe they've fully explored the equipment they have already and can articulate what they think the step up will give them.