Getting back to the main point
The fact remains that if I am going to consider all 17 studio albums as Sabbath albums, or even anything past the original eight albums for that matter, then solo work counts as Sabbath as well. Once Ozzy left, the sound of the band changed, and it kept chaning as people came and went. Even if you don't consider Seventh Star to be Sabbath (as some here don't), the Tony Martin albums only had a single original Sabbath member in them: Tony Iommi.
Martin-era albums had only Tony Iommi, yet we consider it a Sabbath album. Why? The only member from the original band is Iommi. It's as much an Iommi solo album as anything. If I can consider a band with only one original Black Sabbath member in it to be true Black Sabbath, well, then... any band that has at least one Black Sabbath member is Black Sabbath, regardless of what superficial name is given to it.
Ozzy's material may not all sound like Sabbath and neither may Geezer's, but if you listen to songs from the original eight studio albums, there's a wide range of musical styles, from The Wizard, to War Pigs, to Under the Sun, to Am I Going Insane, to It's All Right, to Swinging the Chain. We can accept that such a wide variety of influences played upon Sabbath music, so surely just because something sounds
different doesn't mean it's not Sabbath.
If we consider the Martin-era to be Black Sabbath, then we must consider any band with at least one Sabbath member in it to also be Sabbath. Since I am of the opinion that all of the 17 studio albums are true Black Sabbath albums, I must also conclude that the solo work of each artist is in some way a creative arm of the original band. Obviously, I don't mean this in a literal sense, but it's part of the Sabbath experience.
The only way out of this logic is to say that although Iommi was the only member in the band, he is so important for the Sabbath sound that his playing carries the Sabbath sound alone, and therefore, even in the absence of the other original players, the songs still sound like Sabbath. OTOH, Geezer, Bill, and Ozzy are more inconsequential to Sabbath's sound, so their solo playing doesn't carry the proper Sabbath tone. I could go for that, but it would limit my view of what Sabbath is and unfairly bias me when it comes to certain 'Sabbath' material.........so while I'm at it, I like to include a bit more material. Yes, I have a hard time thinking of Ohmwork as a Black Sabbath record, but just on listening, I have about as much trouble doing that with Seventh Star, Cross Purposes, or Forbidden. Forget the superficial names of the two bands for a second, though, and consider the musical styles and number of original Sabbath members on each album.