A fallen angel took flight as Sprint (S) soared by 20% on Thursday after an interesting June quarter. The overall net subscriber loss number for postpaid subs was not that great at 240,000, but the 1.5 million iPhone customer adds was about 200,000 above expectations. Even more importantly, the key profitability gauge of EBITDA came in at $1.3 Billion — half a billion above what many expected.

That combination is fascinating. AT&T (T) and Verizon (VZ) also had strong profit numbers, but that happened because they were a bit light on iPhone adds. The expensive subsidy support of the iPhone means that operators almost always either beat their iPhone consensus or profit consensus, but never both in the same quarter. Sprint’s combination of strong iPhone sales and a profit pop is what woke up Wall Street on Thursday.

There are three factors boosting Sprint in 2012 after a very rough 2011. First, the nightmare of the Nextel merger is almost over as Sprint winds down the obsolete iDen service and consolidates its subscriber base on its CDMA network. In the process, Sprint is bleeding hundreds of thousands of iDen subs every quarter while it adds hundreds of thousands of CDMA subscribers. That juggling act is finally drawing to an end in 2013.

Second, T-Mobile is a disaster. Sprint used to split the budget mobile market with T-Mobile while Verizon and AT&T competed for U.S. supremacy among consumers who don’t mind paying top dollar. T-Mobile is coming off a spectacular losing streak — a botched merger attempt with AT&T, an expensive and failed marketing campaign featuring a B-list Welsh actress, a weird attempt to pivot from a deep value brand to a high-tech brand, a CEO transition, and so on.

The current “No More Mr. Nice Girl” ad push is also a dissonant train wreck. Using a Zeta-Jones lookalike actress after the Zeta-Jones branding effort flopped completely is a classic T-Mobile USA move. So is trying to sell the concept that the former budget carrier is now offering better 4G service than AT&T or Verizon. Whether the claim is true or not, consumers don’t believe it for a second. T-Mobile’s constant stumbling is handing Sprint a shot at dominating the value segment.

Third, and perhaps most important reason for Sprint’s rebound, is the greed exhibited by AT&T and Verizon.

These two behemoths have gone on a giddy binge of consumer-hostile initiatives. The list is long and dismal: removal of cheap texting plans, forced unlimited voice plans, tiered pricing with rapidly escalating data prices, etcetera. When Verizon boosted the price of its cheapest available smartphone plan from $70 to $90 it effectively created a 28% price hike for new subscribers not interested in big data packages. It also brought the price of the cheapest Verizon iPhone plan very close to the price of Sprint’s unlimited plan.

What industry leader in America can raise the price of its cheapest product by 28% overnight? Here is Sprint’s shot at finally making a dent in the emerging mobile duopoly in America. Sprint’s unlimited iPhone plan is a fairly good deal for heavy users, and Sprint brands like Virgin and Boost offer solid deals for budget iPhone segment — though the upfront payment in those deals is daunting.

The hegemony of Verizon and AT&T seemed invulnerable, but Sprint may now finally have its chance to chip away at it.