Steal equity is greater with 72o than AA because, as pointed out, usually with AA you are betting for value and not trying to steal. However, the concept isn't helpful because:
As cards get weaker usually you lose a lot more in showdown equity than you gain in steal equity.
There are pure stealing situations where showdown value isn't required. The prototypical example is when it is folded to you in the small blind against a very tight big blind. Raise away every time. The steal equity is +EV on its own.
If a steal situation does not have near-positive EV from stealing blinds, it usually requires some showdown equity. (Technically it is when stealing blinds plus c-bet bluffs aren't immediately +EV then you usually need showdown equity.) So raising the button against moderately tight blinds you have enough steal equity that showdown equity doesn't matter. Raising from the cutoff against moderately tight button and blinds usually requires some showdown equity, so you open fewer hands. (Also, the button has such incentive to play that you might fold the bottom few percent of "profitable" hands so he won't adjust and take away a big chunk of profit.)
We didn't publish the stuff I wrote about hand trees, dead money, the equity of folding, and understanding which lines make money and which don't. (By "line" here I mean something like raise preflop, get called, c-bet flop.) One critical example from that is most lines that result in a c-bet bluff do not make a profit. Under typical game conditions, you get called too often for the hand to show an overall profit, but there is enough dead money in the pot that the c-bet bluff is "correct." So c-bet bluffing is a lose-less play instead of a make-money play. And yes, there is a difference.
What this means is unless you make a lot of profit stealing the blinds, you almost always need some backup value (namely, showdown equity) to make playing the hand profitable.
This is where the Theory of Poker approach that "the equity of folding is zero" has messed up a lot of players' thinking about profit and no-limit hands. The equity of folding is NOT zero. It's just that setting it to zero is the best frame of reference to use DURING a hand. But before a hand, when you are thinking about whether to play and how to make a profit, that is a terrible frame of reference. For example, say you fold 72o preflop. That's worth zero right? Ok now you fold aces preflop. That's worth zero too. So if the equity of folding is always zero, folding 72o and folding aces preflop are equivalent. If it is all the same to you, I will take the aces and you can have the 72o. The equity of folding is not inherently zero.
Similarly, folding = zero is a bad frame of reference at the end of a hand. Say everyone is all-in and the pot is $1,000. You have a royal flush. What is the equity of folding? You could say "folding is worth zero and showing the hand is worth $1,000," but a normal brain would think, folding costs me $1,000 since I've obviously won this pot! So for thinking about profit and how to make it, you should give up that frame of reference.
Under usual conditions, when it gets to a c-bet bluff, from there you do not get to overall profit. So you need to think about stealing blinds and hitting flops to "compensate" for the expected loss that results every time you end up missing the flop. Yeah, sometimes they fold so often that c-bet bluffing results in overall profit, but even in current $1-$2 6-max that doesn't occur nearly as often as you might think.
Stealing blinds and making hands are where the money is.
Ok first long tangent over for now. :-)