i don't use elliot waves, bollinger band, macd, rsi, fibonacci, moving averages or even volume etc. i use what works for me. areas of interest...support and resistance based on my strategy and technique (not just any areas of support of support and resistance). i also filter stonks based on my criteria (i.e. 52 weeks high). And not just any 52 weeks high. there are other criteria which i won't go into.
Most that are classified by exchanges as professional and who undertake and manage risk, which excludes those who make markets, liquidity providers, dealers, brokers.
You did not provide a link which proves your claims. Further more - that's only one subset of professional market participants. I know that I personally have never had any interest in being a market maker, nor any illusion that it's something I could do profitably as a retail trader.
Not everyone can call the trades live, which I did as evidenced by lack of edits and multiple other users agreeing. Highs/Lows of day were caught a statistically significant number of times. Wallstreet guys go bust often, they're not invincible. TA is a broad science, not the retail triangle HS trash.
I am also very wary of the notion of "predictive power". For anything. You take the very best risk vs. reward you can, and however you can model it. An awful lot of successful traders that I've personally seen in my career model price, among other metrics.
Evaluating past vs future price performance, the reason charts make sense, is because often what happened in the past still may have the same level of interest in the future. If you don't know what can happen to price, reversal and consequent range expansion, even if it's 50/50 expectation, after it failed to go through a past key level, then if I was a professional trader, I would at least keep this level of ignorance to myself and not go public with my evaluation of past vs future of price behavior #pasthasnomeaninginthefuture
Charts and Technical Indicators are a statistical study whether anyone cares to admit it or not. I would recommend the book Modeling Financial Time Series with S-Plus, by Zivot.