You can't look at it as one big sum. You have to look at it from all sides. Gamers have been conditioned to expect that they can get used games almost immediately from a game's launch. They can wait as little as 3 days and buy a AAA title and none of that money goes to the dev. They can then trade that game in any time and the used title can be sold to another buyer, none of that money goes to a dev. You have a shadow market where only initial sales go to the makers and then the vast long tail they never get a cent from it.
It's leeching out money from Devs hands from the start.
Well, let's be honest about this.. it isn't leaching a dime from devs, because devs aren't paid based on sales of a game and many don't receive any share of the revenue. Publishers get that. The publishing company makes a deal. Now, it may impact the next deal the publisher makes with the dev, and that's true.. but once the game is on the shelf, for the most part, the Dev has basically already been paid 99% of what they are going to get UNLESS they are both a dev and a publisher.. IE, if Activision produces it's own title, etc.
As a follow up to that: so what. This is a bit like arguing the used car market rips off the new car market. It's balderdash. The market is large, and part of what keeps the market going at the price that it is at is based upon perceived value. If you were to buy anything else and be told you could never resell it (ie, perishable) you'd be OK with it.. as long as the price was lowered. But as long as the price stays relatively high - and $60 for a perishable item is fairly high - then you generally want some perceived value out of it beyond what you get now.
Microsoft's strategy failed in large part because it offered a perishable item at non-perishable prices. The developers not only didn't benefit, developers got completely screwed in this deal in that they were told they could not self-publish, they'd have to find a publisher, and small developers were denied the development kits altogether. So the case that "it's good for the developer" seems to point to Sony which let everyone+dog get a copy of the developer kit.
I think it's well known here I normally defend Microsoft.. I know too many people there, and quite a few of their products I really like.. but this was a disaster in planning from the get go, and even though this change is a step in the right direction, their move against small developers is still the wrong idea that is anti-developer, and in the end, will hurt their game marketplace from finding the next big thing.