I disagree, I don't think technical analysis is just self fulfilling prophecy.
Technical analysis is nothing but
studying mass psychology. People behave in predictable patterns when placed in a herd.
Technical charts had been working even before the study of technical analysis began.
You can look at the chart of the
Tulip Bubble which occurred almost 400 years back, you will see a nice uptrend (bubble) followed by a downtrend (subsequent crash) which is the building blocks on which TA is based.