Ubisoft still has the rights to both it and Exile and Cyan has attempted (unsuccessfully) to acquire the rights/work out a way to sell the games digitally.

Outside of a miracle, both games seem doomed to rot under control of their publisher.

We got End of Ages, so who knows.

Ubisoft was the original publisher, not the developer though. With Revelation, they were both.

I don't know what the rights are like exactly, but purely guessing - it would seem likely that Cyan has (at least) ownership rights to the Myst name and that may be what's preventing Ubisoft from even lazily putting out a digital package of Revelation on their own store.

Ubisoft has its own issues though and if (or more likely when) Vivendi completes its takeover of the company, it should be interesting to see if they move to get rid of any properties that Ubisoft has held onto but done nothing with.

Cyan has finally acquired the rights to Myst III and IV.
They are planning a release.

Myst IV AND Myst III. GOG, you rock my world. THANK YOU!!!!!

I really enjoyed Myst IV. The artwork is stunning, and the control and motion was smooth. I must admit, I had a little trouble getting the Mangrees to trap and poison the Camoudile, but that was all part of the challenge.
I didn't buy this game, or any of my other Myst games from GOG, however, only because they didn't offer them in the Macintosh version. I had to get the Mac versions elsewhere. Too bad, but at least, for all you PC users, I totally recommend this and all the other Myst games. Have fun.

Yes, Cyan said in a press release that the re-releases would all be centered around Windows10 (Well, Win10 backwards compatibility often extends to Windows 7 and 8, too, but on the whole I have found the latest version of Win10x64 to be more backwards-compatible with games than either Win7 or 8.) Except for the original releases of Mysts III and IV, which I couldn't get to run in Win10 no matter what I did...;) The re-releases have removed that barrier, so thank you for the recommendation.

Just curious, was your OS X version of Myst IV tied to an emulator? Lots of so-called Linux and OS X-compatible older games actually run on emulators like Wine or Boxer, which few like--only because the original games were never made for Linux or OS X, of course. If so, you might consider bootcamp, although whether Apple has created it to be Win10-compatible, I would not know. Still, I think you'd be OK with even a Win7x64 or 8.1x64 version of bootcamp, most likely. But, keeping up with two OSes like that can be daunting, no question. At one time I was running three OSes simultaneously...! Got to be less fun and more work so I swore it off--no more tri-booting for me.

Does anyone know what resolutions the GOG version of Myst IV will support? The original release apparently only supported 800x600 and 1024x768. Thanks.

Still the same. 800x600 or 1024x768
There is a third party widescreen mod floating around the net. Haven't tried it yet, having issues running Myst IV.

Mac versions of all the games, including Myst III and IV (albeit running in Wine) are coming. The original was a native PPC (non-intel) port, but the new one will be a wine wrapper.