In regards to selling CD-compilations of old software, it's an area that can be fraught with controversy and can upset a number of people. If anyone is thinking of doing this, I would advise caution.
In the TRS-80 Model I/III/IV world, up until this year we had a great archive of software available for download from a TRS-80 site. The archive had been collected, compiled and catergorised by the owner of the site.
A while ago someone downloaded this whole collection, put it on a DVD and posted the DVD on e-bay, for sale to the highest bidder.
I don't know the ins and outs...whether it was because the owner of the site objected to the collection he had painstakingly collected and classified being sold for profit by another, or whether some of the software authors who had given permission for free downloads from the website objected to their work being sold in another form, or a combination of both these things or even something else entirely....
Whatever the reason. the point is that software archive has been pulled from the web and the TRS-80 world is the poorer for it.
Vintage software, although still under copyright, has no commercial value, and most authors (but not all) have no objection to sharing their work with retro-computing enthusiasts. However, some people may get upset if they see someone else making money from their efforts, be it as the original authors, or a compiler of a "collection" as such.
My advice is if sharing vintage software, don't do it for any kind of profit and give credit where credit's due. Technically it is still illegal. It's impossible to check with all authors to get the OK for distributing their work. I think it's reasonable to assume most won't have an issue with it. However, if an author does object, respect those objections and don't distribute their programs.