Naturally. There isn't only one future in a sense, and a trading chart could only show one future. There can be said to be an n amount of futures in the universe, and no matter what, one just can't simply predict what would happen in the next minute, hour, day, week, etc. Trading charts are something that let you make a decision based on what you see, but that doesn't mean that it would be the only basis you have on making a decision. It's not like you'd decide to enter a school for pilots just cause you saw your crush there right? And even if you did, that'd be called impulsive decisions. Even having 2 or 3 factors while deciding could still be said as an impulsive one.
I guess even 70% is a little too much ain't it ?
Imo, yes. Though you can at the very least put it at the minimum of 50%, since if you were to look at it as to whether you'd only lose or win, chances are 50/50 no matter what TA's you read, no matter how many analysis you do.