TTT is an occasional event, it's not mandatory. Even when they do it, they try to keep it short because time gaps can be huge otherwise. There's always a Spanish or Italian team who's absolutely terrible at it, and it ruins at least one GC contender.
You wouldn't be asking about a more competitive race if Froome was putting 5+ minutes into all the other gc contenders over 80kms. I think they had too many years of Lemond, Indurain, Ullrich, Wiggins and (sometimes) Lance only winning TT stages on the way to the the Champs Elysees, so the race is definitely more set up for climbers these days.