Nigel, do you think the bikes ridden by the people you mention above bear much resemblance to the bikes purchased by us mere mortals?
When I bought my son's first Gas Gas the supplying dealer said "if you're riding it you'll love it, if you're paying for the repairs you'll hate it" and he was right! After umpteen gearbox rebuilds, new clutches, broken rear suspension linkages (none of which happened with his Montesa or Beta bikes) I'm heartily fed up the gasser. Fine if you have factory or dealer support.(and I'm being a bit careful here)!