Deep discounts don't "devalue" games, they bring in massive increases in revenues when done correctly. For example, in a particular experiment that Valve performed a 75% reduction in price resulted in a factor of 40 increase in gross revenues. It's hard to argue with numbers like that.
A $60 title being discounted to $15 and seeing a 40x revenue spike is pretty cool. One of the most amazing indie game packages of all time earning a team of devs less than $1 per bundle sold is somewhat worrisome to me.
I mean it's the same for every product. The first computers were ridiculously expensive before becoming ridiculously cheap. It's all about the cycle of "early adopters" then reaching the mass market. If you want to reach the mass market with your games, it's much easier to do so by lowering your price. Doing TV marketing works, too, but it costs so much money it's not even for the same league of games. You can only do TV if you expect to sell several millions of it.
Anyway, back to my point: not all gamers want to spend 60$ in the first place. Some won't. So they will either buy your game at 5$ or never buy it. The rest is all about lost opportunities.
Seems like the people that play games would have already bought and enjoyed the most appealing of these sometime in the past couple years. If they see this bundle and take the opportunity to pick up the ones they didn't care as much about on discount, that's a win for the developers. And for people like me who would never buy or play them otherwise, I get it cheap and the developers get at least some money from me (and an email address to market to :)).
Doubt there's many hardcore gamers who've passed on the full price games in favor of waiting years for these to be bundled and discounted. So these bundles seem like an amazing way to eke out a couple hundred thousand extra dollars from an audience that you wouldn't otherwise have reached.