Hi...
It looks to me like someone managed to obtain the rights to all those old Microprose titles, for sale on Steam. For instance, you don't see European Air War in Steam's list, because MP sold EAW to Hasbro, and then it was sold by them to someone else (it's been a long time, but I think Hasbro sold it to Atari). Look at the screenshots, and the system requirements- nobody's done a thing to them! Boy, those were the days- I probably still have my copies of EAW and 1942- a friend gave me Mighty 8th, but I never got it going... hours and hours of EAW on my Pentium II, with Windows Me and my Voodoo 3000 card...
-Mike Z.