Still, Bale with 2 years left on his contract isn't going to be as valuable as Bale with 3 years. Clubs will use that to lowball Spurs. There are tons of examples of top class players leaving on the cheap with one year left on their contract. Why didn't RVP move before last season? Clubs would have been sniffing around him but Arsenal didn't want to sell. Spurs might not want to sell (for a realistic amount) next summer. You're not going to get the £70m everyone thinks Levy will sell for with 2 years left on his contract IMO. They apparently can't even get that now.
You wouldn't be a tad worried, if you were Levy, if Bale didn't sign a new contract before this time next year? I wouldn't want to take the risk of a Van Persie/Kagawa or even a Lewandowski situation happening. Bale gave it his best shot, Spur didn't qualify for the CL, he'll have two years left on his contract next summer and will probably want out, CL football or not. Now is the time to take the money and invest it in the squad (strikers).