I guess that depends how we look at the concept KFW has in the OP. I'm starting to think maybe he has a different idea in mind than I originally read in it (since he's clarified he's talking also about doing this repeatedly). So, if I spent a concentrated period of time (okay, maybe not 2 years, but let's keep that for discussion) working on my hip throw, I'd want to also work on how to set it up. That would be part of training it extensively. So, I'd have to work on the flow from other techniques into a hip throw. Then I'd want to train recoveries - the better I can recover if the throw fails, the more confidently I can commit to it. So, I'd train working from various points of failure in a hip throw into other techniques.
So, if we broaden the concept from only training one technique to training AROUND one technique (the set-ups, the entrances, the recoveries, the exits, etc.), then maybe it makes more sense.