Tibet came under control of the People's Liberation Army in 1950. In 1959, there was an uprising which was supported bythe CIA, and the Dalai Lama, who had been allied previously with Beijing, broke with China and escaped to India.
The reason this question is hard to answer is because at no time in its history has Tibet ever had a western-style liberal democracy. Before it came under Chinese control following the Chinese invasion of 1950, it was a theocracy with the Dalai Lama as a god-king. Unlike the pope, he held the power of life and death over his subjects, and land was held by the lamas who were senior clergy similar to Catholic bishops.
If Tibet never had a tradition, or even had anything which vaguely resembled western liberal democracy, how is it going to form in Tibet? Is it just going to sprout out of the ground spontaneously? That hasn't even happened in Iraq following a US invasion and nine-year occupation; how is it going to happen in Tibet?
And how does the Dalai Lama's "commitment" to western liberal democracy count for anything? He does not control Tibet, he doesn't have an army and he doesn't collect taxes. Moreover, there is almost no chance that he will return to Tibet in a ruling position in the near future. So how does his "commitment" count for anything?
He can say anything and it doesn't count for a damn thing except for a group of westerners with romantic ideas about how Tibetans should live.
For this reason, this is a moot question. At best, it's hypothetical and at worst, it's conjecture.