The best thing for them to do is to include them with non-freeware sequels.
Lets say they got the C&C games. They could have a C&C collection that included "newer" C&C games like Red Alert 2 but also the original Red Alert (which is now freeware). Elder Scrolls could have Arena + Daggerfall, etc.
This way the classics get distributed but it's not just free bandwith for anyone who wants to grab it. You'd be paying the $6 for the goodies and the work that gets them working on modern systems, and probably wouldn't feel ripped off because you're getting more than one game.

I think it's a great idea.

Hey, I love that idea :)

to reanimate this topic:
i think its a nice idea.
whats about a statement of the gog-team?

I'd be more than happy to pay $2 or $3 for GTA, Red Alert, or Arena knowing that it will work in Vista, and I could download it from here whenever I wanted. I vote yes to that!

Even longer than that. A basic copyright for a work created by an individual lasts for the life of the author, plus 70 years (easily over 100 years in most cases). Copyright for works created for hire last 95 years from the initial publication or 120 years from creation, whichever comes first. Most commercial games fall under the 95/120 year rule, and that's assuming that no one tries to renew that copyright before its expiration. We'll all be dead and buried before most video games come out from under their respective copyrights.

What a weird but beautiful sentence... It kind of reminds me the old books you can find on wikipedia who went into public license. Art :D
I hope one day in the future somebody will think about building some kind of library will be established with great old games available for free.

As much as I'd love to see free content on here, I highly doubt it's going to happen for a few reasons..
1. Content servers require moolah and free games don't deliver moolah
2. Really only hard core fans are going to pickup free titles, I can list of half a million free indy games that I just have no desire to play, simply because I am not inspired to play them. Free games usually don't have much advertising for them and are for a niche market.
I'm all for it, but don't see it happening.
EDIT:
I don't see it happening without the publisher offering games you have to pay for on the service as well.