Progression betting system is *not any worse* than flat betting (if the hand was dealt from a fresh deck every time, and etc etc). If you are playing an even game against the house (i.e. 0.0% edge) *for every hand*, it does NOT matter if you use flat betting or any other exotic/clever/"power" systems. Your *expected* return after many many hands will be zero. Now add a small edge for the house, and your expected returns will be some negative amount of dollars after a certain fixed number of plays (without counting cards). Again, that expected value will be *the same* no matter what kind of betting system is used (as long as the average bet (over a large number of plays) is the same for different systems, and etc etc). This is what we call science (math, statistics, or whatever).
I see there are two (very strongly) divided "factions" in AP community regarding progressive systems, and I can see where each side is coming from.
 First of all, you cannot argue with (proven again and again and again...) science. There is no "your" science or "my" science. You cannot invent a perpetual-motion engine! Period. You just cannot beat (statistically) unbeatable games by merely using some clever betting systems. I see why some people on this board feel so strongly against these betting systems (so far as to go to suggest to censor any posts related to them).
 But, then again, please notice the assumptions (sometimes just noted as "etc etc") in my arguments above. Any theory (we don't use the word "truth" in science. Even the "fact" that a rock thrown in the air never fails to fall onto the ground is called (or described as) Newton's "theory".) is only valid under certain (well-defined) assumptions (or conditions). For example, Newton's theory of universal gravitation is only valid in moderate strenths of gravity, and it breaks down in extreme condistions like in black holes. Likewise, Newton's (another) theory of dynamics (the famous f=ma) is only accurate when the speeds of objects are low (in extreme conditions, Einstein's special theory of relativity is needed to accurately describe the dynamics). Likewise, these progressive betting systems are only "proven" to not work under some (explicit and/or hidden/unstated) assumptions. Can the "dynamics" of BJ be accurately described with a well-defined and *solvable* mathematical model (as a stochastic process)??? I don't know. For one thing, each hand is NOT drawn from an iid (identical independent distribution), and that's exactly what AP exploits: The distribution of cards changes as the deck depletes. I don't know of any theory that proves/disproves any one betting system is better or worse than any others in "real" BlackJack games. My point is, it's an open question until somebody comes up with a rock-solid proof that progression does not work in BJ.
Just my two cents,
BTW (1), if you ask me, I think I personally belong to the first school of thoughts (); you are innocent until proven guilty (that is, the burden of proof is on the side of ). But, I'm very open-minded toward . (Actually, I suspect positive progression systems should outperform (slightly, if ever) the flat betting system for exactly the same reason why the card counting/bet spread (is supposed to) work. (Please think about it!))
BTW (2), but then again, with so many simulation softwares etc out there (although I've never used any of them personally, and I don't really know if it's possible to do this kind of simulation), how come nobody on the side of  has come up with some solid *data* to prove their systems work. (Remember, the burden of proof is on the proponents of . If you discover a way of time travel, for example, *you* need to convince the rest of the world (that is, if you want to take a credit for it ;-).)
BTW (3), if it matters, I have some formal education in stochastic processes.
BTW (4), if you come up with a working progression system, PLEASE share it with us!!! (But, "it works for me" argument will not be enough. Even if you said, hey, I just won a super-lotto using my 'power system', and waved around your millions of dollars in my face, I would have no interest in your system.)