I think this is a really great question, and that it makes a good point. It should, however be a bit more specific: Do any well-known pro players regularly use synthetic reeds on their primary instruments? It's important to make this distinction because: 1) most pros have undoubtedly tried synthetics at some point and what we'd really like to know is whether they stuck with them or went back to using cane; and 2) I've known people who, say, mainly play cane reeds on tenor (and would never use synthetics on this horn) but nonetheless play synthetics on alto or soprano for the convenience, since they don't play those horns as regularly.
I think the answer to this question is important precisely because of the inherent advantages of synthetic reeds (e.g., longevity, consistency, convienence, reliability, etc.). If I found a synthetic that responded at all like cane, I'd drop cane reeds in an instant. I've tried a number of times to drop cane. I hate the inconsistency of cane reeds. You get everything together: work like a dog on technique, make sure your horn is working perfectly, do overtone exercises to get yourself solid on your horn and mouthpiece, and then you have to switch reeds and everything changes. I've tried a number of times, for several months at a time, to get used to different synthetics (and I'm about to try again), but haven't found anything that works.
So on the one hand, I say if you found something that works, stick with it. But if a synthetic exists that plays as well as cane, I imagine that just about everyone would switch. So, in light of the advantages of synthetic reeds, why is it so hard to find a big name player that uses them?