A: The number of Tai Chi styles today is very large because many teachers changed the old styles or created entirely new ones mixing in there own ideas. But the fact is that the three old styles from before 1900 had the original principles intact to a great degree, each in their own respective way. There are many good teachers today, but there are also teachers who never learned the original principles of Tai Chi, they may not even be aware of this fact. For this reason, I think it is very important to describe and destinguish the old principles of Tai Chi so they are not lost.

List of nearly 100 Tai Chi styles on Wikipedia