You are right. Steve isn't using an R20. I probably shouldn't say this, but Steve used his Kashy for most of the events last season. I'm not entirely sure what he's using this season, but I wouldn't be suprised if he has a few different fins as well as his old trusty Debs. Let's not forget that traditionally, Steve uses the fins that nobody else uses. He won the 2006 Worlds with an R16 in 6-8 knots! Nobody else could get that fin to work on the F160! So I wouldn't take to heart exactly what he has under his board at the events...
Another point to mention is that the reason you'll probably find that a few more of the top guys are using Kashy fins is that I'm sure they are getting fins designed specifically for them. Take the R20 for example; its available in one stiffness and make only. That's fine; I'm sure its a fantastic fin - but what if I wanted the same fin with just a little more twist at the tip because my sailing style required this? I know not all fins work for everyone and so you'll probably find the top guys wouldn't do well if they sailed each other's fins. When Jesper Vesterstrom was here in Australia in January I tried some fins of his and I thought they were terrible. He's been Top 3 every event this year on them... is that to say his fins aren't very good or that his sailing style is completely different to mine and requires different fins?
Being able to work with a fin designer on your own ideas and concepts is pretty special, and not really applicable to most of world's FW sailors. Welcome to the fastlane of being a pro-rider (these guys are always going to have access to better gear than you). I suspect that's why so many guys have gone searching for Kashy fins and to some extent Hurricane (as Otmar seems quite happy to build you a "you" specific fin). Deboichet is presenting a more 'mass-market' approach to the fins offering only one make/characteristic with the R20, but that's why its one of the cheaper fins on the market (compared to Kashy especially!) and available in relatively low waiting times. I realise having fins only available to certain people at the top is counter-productive to the sport; but that seems to be the norm in FW these days. However, there appears to be new fin manufacturers popping up this year, so maybe that will help distribute the wealth a little more evenly.
That being said... I don't believe you've wasted any money on the R20. I think it will be a very good fin this season. I think they are just simply a little less represented at the front of the fleet because there aren't too many out on the market as yet.
I know at least quite a few of the Dutch guys have got R20's. So there'll be a few popping up at the FW Europeans when the Dutchies come to race