Buchanan knew that he could question the technique and temperament of the greatest batsman, Sachin. So he came up with an idea—which is true in general for ordinary people that they become less inventive and fearless when they grow old—that Sachin is not inventive and fearless at this stage of his career.
Which is not true in case of Sachin who is doing excellent in ODI and test. I think to succeed in ODI and Test a batsman has to be more inventive and fearless when oppositions have much better technologies to analyze a batsman.
He has followed Adam Gilly methods. Like Gilly he knew that to sell his book in India or force Indian to buy his book he had to say something against Sachin and other greats of India and he did that.
Warne—who is a great cricketing brain and analyst of the game—has said many times, though indirectly—that Buchanan is the most overrated coach. It is only Indian media—having a habit of hyping ordinary people—that has hailed Buchanan as great analyst cricket analyst and gave him more than required importance.
As for me, Sachin has been and is still the most inventive and fearless batsman in the world. I am sure if he plays T20 internationals he would be as successful as he is ODI/Test.
Buchanan is mentally sick person, who has the habit of overusing using his empty brain.
This is all to make money out of Indians to sensitise and make them buy & read books, which worth nothing. Best way is to ignore and ensure that these people don't land in highly paid jobs in India, when they doing nothing special. By the way, books of Gilchrist, Simonds etc and i am sure now Buchanan are available for $10 in Australia, but nobody buys them and will son be in garbage bin
If he was not privileged to captain a super Australian side nobody would have even known him. Wat Gavaskar said is rite. His inefficiency was proved when he coached Kolkata knighriders. He took the team from failures to more failures. Who is he to comment about the God of cricket?
Buchannan wanted some publicity. So that people buy the book. Indians are the maddest when it comes to cricket. And creating enough publicity here, he can expect his books to sell well.