Superlative performances in friendly conditions dont make up for below par performances in away conditions. Otherwise Murali should be rated far higher than any bowler in history based on his insane home numbers plus very good away numbers.
What Ashwin has done is impressive but hardly unique. There are plenty of other spinners who have world class figures and plenty of matches won in their own backyards but are lacking away from home, such as Herath, Jadeja, Yasir Shah or even Kumble. You can already foresee someone like Axar Patel ending up with similar figures by the end of his career. Its not that big of a deal.
Not sure where this is coming from. The only place where he has really struggled is South Africa, and he has only played 3 games there. He had a bad series in Australia and went back there as an improved bowler in his remaining outings.
You need to read up more on Indian cricket, I think. Ganguly himself said how much Kumble hated that and they were not even on speaking terms at a point. Dravid had to go and talk to Kumble. It definitely was stubbornness on Ganguly's part, coz unlike Jaddu, Bhajji was not even helping us win or anything. He just kept sucking and honestly was not all that better a batsman than Kumble either.
I have been watching the game since early 90s, and I think Kumble being kept out of the side once in a while for improving the team composition is being blown out of proportion here. It is no where close to how Kohli treats his players.
It was tough to deal with the likes of Bhajji, Kumble, and other legends that Ganguly had in the team. Whether it was shuffling the order or keeping one of the bowlers out to try out a different combination, it was tough. But the difference is communication, all players under Ganguly knew that they wouldn't be just randomly dropped or left out of the team for long periods without any reason, things like this create a feeling of security and get the best out of players.
In Ganguly's own words:
"My biggest challenge in that era was to tell either of Harbhajan or Kumble that you're not playing in overseas condition. If I tell Anil in seaming conditions in England that Harbhajan has 50 wickets in a year, you take a break in this game, he would say I've got 400 Test wickets."
"I remember in Brisbane, we had to leave Anil out of the game. After the match he came to me and said I want to go back and retire. He had so much pride and was such a champion that sitting out hurt him. I had to somehow hold his hands and say Anil I'll get you to play, don't worry."