Major wireless carriers have been playing musical chairs with their top executives lately. Spurred by the volatility of the wireless mobile market and the huge stakes involved, companies have been quick to change management horses midstream.

AT&T has now gotten with the program, promoting Ralph de la Vega to be CEO of the company's newly merged mobile and business units.

He moves up from president and CEO of AT&T's consumer mobility group. Now filling that position on the company flow chart will be Glenn Lurie, a longtime AT&T exec who was famous for engineering the multiyear exclusive iPhone deal in 2007 that AT&T enjoyed with the first-generation iPhone, an arrangement that worked spectacularly for them, not so much for Apple. Lurie's most recent assignment within the company was as president of the emerging enterprises and partnerships business.

De la Vega's role will consist mainly of merging the mobility group with the business group, an acknowledgement that the company recognizes the primacy of mobility as the main driver of its business, combined with the fact that business-related customers represent over half its mobile revenue.

Lurie will report to de la Vega, who will report to AT&T CEO Randall Stephenson.

The changes at AT&T occur in the wake of changes at the top at Sprint, where Dan Hesse vacated the big-boy chair to pursue other opportunities, as corporate-speak dictates. As reported in Tech Times, Marcelo Claure was brought in from Brightstar Corp. to take over as CEO, as Sprint continues to be beset by logistical and sales issues.

T-Mobile has been led by CEO John Legere for only about two years. After the collapse of the proposed Sprint-T-Mobile merger, Legere and Sprint have engaged in both a war of words through Twitter and some flamboyant restructuring of their mobile communications programs for consumers, in what seems to be a race to the bottom. Most recently, T-Mobile went after AT&T's mobile share plans by significantly lowering the cost of its own unlimited talk and text, 10-GB data-share plan compared with the cost of AT&T's popular plan.

AT&T is surely viewing the skirmish between T-Mobile and Sprint as a cautionary tale. Although AT&T sits comfortably in second place in the Big Four of wireless carriers, changes occur too quickly for the company to be sitting back on its heels; thus, part of the rationale for the corporate leadership reshuffling.

Both de la Vega and Lurie are considered aggressive, proactive leaders. Whether it's enough to keep AT&T in growth mode will soon be revealed.