As to W&P's lifts, I don't know why couples that prefer to stick with tried and true lifts do that. The Kerrs do it too. Perhaps I'm spoiled by the Shpilband teams who have some new lifts (if not all new lifts) every year.
They've certainly created some gorgeous Lifts, but not all are entirely original. Igor & Marina aren't averse to checking the T&D archives (both for Lifts and musical inspiration!)