Fellow Scot Clarke believes the Manchester United manager could be the last of his kind and should be admired while he is still going.
The Baggies boss said: "I have met a few grumpy 70-year-olds - he is a typical grumpy Scot. He likes to go chasing and he hasn't lost his hunger or his desire.
"I worked with Sir Bobby Robson at a similar age and he was maybe not quite as aggressive but he had that determination and will to win. It is great to see."
Clarke admits the demand for instant success and the rewards it brings means there is unlikely to be another Ferguson, who has been at Old Trafford for over a quarter of a century.
He added: "I don't know if I'd last until 71.
"I think it would be great to think there could be someone like that in the future, someone who has that longevity. But the way the game has gone it is more short term.
"It will be really difficult, if not impossible, to match his achievements. That goes without saying. It will be much harder to build a dynasty and be in a job as long as he has been."