60 years is long enough to conclude if a cause is successful or it is a failure. After 60 years, the Tibetans are still in exile, there is no progress in Tibet cause; there is no clear direction from the CTA. It will be very unfair to ask the Tibetans in exile to keep waiting for the day to come and more unfair to India and the west to continue to give support in any kind.
The Dalai Lama's change of tune is an indirect way to tell the Tibetans and the world that the Tibet cause is a failure. For the future of the Tibetans in exile, it is better to negotiate for autonomous recognition for Tibet than keep fighting with the Chinese government. Tibet is so developed now, there are schools, hospitals, houses, roads, train, airport. It is modernised like the rest of the cities in China. People are given the freedom to practice a religion as long as they don't mix politic with religion and they abide by the law.
If the Dalai Lama is accepted by China, he could bring the Tibetans in exile back to Tibet and enjoy everything China has developed in Tibet and they will have an identity, not stateless anymore. What can the CTA give to the Tibetans in exile? For the past 60 years, Tibetans in exile are still stateless, the Indians are angry with them because they leech on India, and contribute nothing to Indian's economy or development.