If AT&T merge with T-Mobile, does that mean that T-Mobile costumers can buy AT&T phone?

T-Mobile cutomers have always been able to purchase AT&T phones and vice cersa the only thing is you would have to call Customer Service and unlock the phone if it isn't unlocked already. Or you can just google unlock code for the make and model of the phone and do it that way. I used to unlock iPhones all the time it's really simple, but I figured that if they do actually merge then T-Mobile customers will only benefit by the phones because AT&T is too expensive for no good reason.