Gundato: The fluctuation only really occurs around when the sales go live, and that might be a matter of propagating the updated data. As for the TWEE:DC price increasing, I suspect that was intentional :p
Anamon: It happens regularly, and it's not just a delay, it's wrong prices. Data has been propagated and updated, but apparently to the wrong values. It's just one of a few things (albeit the most annoying) on Steam that constantly make me go "how hard can it be?"
Gundato: As for being a "considerate buyer". Gasp, shock, and amazement. You need to do research to make an informed purchase? :P
I guess I'm just nostalgic for the days when you could look at a PC game box in the store and, if you thought it looked interesting, just buy it. Less problematic in online stores as you have research at your fingertips. But it's annoying and completely unnecessary. I can buy any DVD, Blu-ray, music CD or console game spontaneously and know it will work, but if I don't have my smartphone with me to do web research, I'm screwed when it comes to PC games. Even worse for used games, online or retail - good luck finding out whether this is a game that could potentially be useless due to online activation or binding to an account. Of course this is why publishers are doing it in the first place, but it pisses me off that they're getting away with it.
Slightly related to what I wrote above about the Steam fanboys defending its higher prices - I've seen the same happen in this topic. Players actually defending publishers' actions because "they are entitled to prohibit/take a share out of the used games market." How can it be that corporate brainwash works so well here, actually convincing people that for some reason, games should be different than any other product in the world where, if you buy it, it's actually yours? Good luck in ensuring consumer rights if consumers are so easily convinced that being scammed is in
their best interest.
The prices fluctuate "regularly"? Really? I have never heard of it happening except for during the major sales, and rarely during a daily update. Sometimes there are hiccups, but that is to be expected (and we notice it because Steam is much bigger than Impulse, so the propagation is more noticeable)
As for your second point: Okay. But that has nothing to do with Steam, and is more a complaint against PC gaming in general.
As for the last part: Oh noes! you have opened my eyes. I am a brainwashed sheep (I assume that was the point).
Like I said, blame the retailers. Sure the publisher is milking us for every penny they can get, but the reason why a digital copy and a physical copy cost the same at launch is because of the retailers. And the reason that the digital copies tend to go down in price more slowly is once again the retailers (the Gamestop down the street has a lot more freedom than Steam).
Either way, please don't confuse your rants against DRM and PC gaming with those specific to Steam. There are already enough things wrong with Steam in particular (regional restrictions come to mind) that it doesn't need you to start using it as an opportunity to whine about the things that annoy you with the platform in general.