Yoga is not really comparable, because it is much more static.
Of course, there is nothing magic about the Tai chi sequences and many other sequences of movements executed in a similar manner should have a similar effect.
A general stretching and mobility routine could be equivalent, but only if it would be similarly complete in exercising the whole body. Presumably the manner of executing Tai chi sequences, i.e. slowly and with appropriate respiration, matters.
The advantage of Tai chi sequences or of other sequences derived from Chinese martial arts or their Okinawan derivatives, i.e. various karate kata, is that in comparison with general stretching and mobility routines they are like reciting a poem compared to reciting a few pages memorized from a dictionary.
Such sequences of movements that have a meaning are both more pleasant to execute and easier to remember in every detail, to avoid skipping some parts.
Of course, there is nothing magic about the Tai chi sequences and many other sequences of movements executed in a similar manner should have a similar effect.
A general stretching and mobility routine could be equivalent, but only if it would be similarly complete in exercising the whole body. Presumably the manner of executing Tai chi sequences, i.e. slowly and with appropriate respiration, matters.
The advantage of Tai chi sequences or of other sequences derived from Chinese martial arts or their Okinawan derivatives, i.e. various karate kata, is that in comparison with general stretching and mobility routines they are like reciting a poem compared to reciting a few pages memorized from a dictionary.
Such sequences of movements that have a meaning are both more pleasant to execute and easier to remember in every detail, to avoid skipping some parts.