Don't get me wrong, in a hall of Fame scenario they make it, but even in those scenarios there are layers to this. There are the first ballot unanimous guys, then there's the 3rd ballot guys who barely scrape in. The term All Time Great means you transcended the sport, you're the fist ballot HOF guys, the top tier of what the sport has to offer. Anderson are none of this things, he played for a really long time and improved over time, but he's extremely conditions dependant and can be toothless when he doesn't have them. That's not nearly how I look at guys with that tag. It's like Curtis Martin vs Barry Sanders, because you have more years because you played a long ass time doesn't mean I mention you both in the same breath.
To your last point, if Shane Warne played with Jadeja, Jadeja would have been relegated to McGill status. He would be the one who payed when conditions suited two spinners not the other way round, that's my point. You can't be the guy, who gets replaced by a guy that's equally poor outside of the SC. We're skipping that point.
In 10 matches in Australia he averages 42 with a s/r in Sobers territory. In 7 matches in England he averages 28, in South Africa an average of almost 50 and a strike rate of over 110.
If as a spinner you're only great in conditions where the opposing team are forced to play 3 spinners, and have those numbers abroad, then I can't see the argument for being an ATG. That's what we kill Weekes and Walcott for, and btw using them as not to pick on players of any other nationality than my own.