Marketing and channels of distribution. Back in the old days, NIKE wouldn't go near Sports Town/Sports Authority. Neither would PING and quite a few other high-end golf lines.(Didn't keep 'us' from bootlegging quite a few sets of clubs from 'somewhere'.
)
It could be about brand image and service at the point of sale. For example, many Sports Authority locations don't have in-house stringing or dedicated department staff. Virtually all of their rackets are sold strung. Not Babolat's game plan at this time.
The day could come that you would see Babolat appear in the 'big boxes'; just depends on the company philosophy toward the 'big score' vs specialty shops and pro shops. Also might depend on 'discovering' a surplus of thousands of rackets that aren't moving through current channels. Then Bab might find itself in 'panic' mode and need to unload a really large quantity of merchandise through one vendor.
Frankly, if Bab doesn't 'need' to go to the 'big boxes', why should they? TW has certainly made it easy for consumers to find the Babolat line...I'm not sure Sports Authority could offer a big boost in sales.(BTW, knowing what I know, I would sell through Dick's before Sports Authority; but I wouldn't expect a change any time soon)