Yes, Verizon is a legitimate threat to AT&T. If Verizon can manage to do a better job than AT&T at luring consumers to do business with them, they will give AT&T great competition. AT&T is too big and many people do not like doing business with them - Verizon will give those people a legitimate choice.
Verizon, AT&T, T mobile, they are all threats to each other. I am sure there are other smaller competitors but all of which are in complete competition.With there advertisements and hiring celebrities to do there ad campaigns, they are all seizing assets from each other for there own profit. Let the games begin.
Verizon has a $120 BILLION dollar revenue (2013) and $275 BILLION in assets (2013). This company would be a threat to absolutely any competitor anywhere in the world. AT&T are another very large company but since loosing the iPhone exclusivity several years ago there is no reason to think that AT&T have any single market section that could be described as unassailable.
No, Verizon is not a legitimate threat to AT&T. AT&T is a very large company, and any competitor that truly threatens them will be bought out by AT&T. As AT&T continues to grow, the chances of any company truly being a threat to them continues to decrease. The buying power of a company that large is too much to overcome.