Wishbone: Chalk it down to experience.
Actually, no I won't. As in my experience, this hasn't been as bad as everyone consistently makes it out to be with the sole exception of POP (and that's only because they then refused to even release it).
Navagon: Apart from when they go down. Which is a given with older games that aren't made by Blizzard. There's also the fact that prices haven't risen in a decade now, if not longer.
Perhaps that's a given in your region. It's not here. Prices of new games go up. Old games rarely get a price drop. Even Activision's and Ubisoft's current pricing of $50 to $60 for a PC game is cheap by our current standards where the average price for a triple A title is $70 to $100. Only 1 such title has seen significant price drops (and that's the failure that is FFXIII).
As for the pricing of the DLC, we'll have to wait and see. But if it's sold over Steam, you can expect some form of discount at some point (at least in the case of Codemasters).