On June 28, 2021, Square Enix posted and pulled a trailer saying Final Fantasy Pixel Remaster series game(s) would appear on PCs via Steam and mobile devices in July 2021. Later that same day, the Steam pages for two Final Fantasy PC ports revealed they are on the cusp of being removed. Both the FFV and FFVI Steam pages say the games will be delisted and “no longer be available for purchase after July 27, 2021.” [Thanks, Lashman and Wario64!]
Here is the full statement from the product pages. Note that the FFV Steam page also mentions FFVI in its notice, rather than the correct game name.
This game will no longer be available for purchase after July 27, 2021. Instead, please purchase the pixelated remaster version of "Final Fantasy VI," coming soon.
Note that this only applies to the more straightforward Final Fantasy ports like FFV and FFVI. While there will be Final Fantasy Pixel Remaster versions of FFIII and FFIV, the 3D remakes of both games have no such warnings on their Steam Pages.
Both Final Fantasy V and VI will be among the six games in the Final Fantasy Pixel Remaster series. Based on the pulled Square Enix video, those should begin appearing in July 2021. The FFV and FFVI PC versions on Steam will be delisted and no longer available to purchase on July 27, 2021.