There wouldnt be a single share over a long time frame that...

There wouldnt be a single share over a long time frame that hasnt had significant peaks and troughs. If you are able to tell when a downward trending share is about to head back up, or a rising share is about to peak and will head back down, then you will make millions. You might be able to do it, but I think most people will acknowledge this involves luck as well as skill (outside of, perhaps, spec bubble shares where you can predict the price will fall at some stage; but not the timing nor the peak).

The people who have done it successfully on the same share are generally exhibiting 'survivor bias' - for example, you may have sold NEU at (say) $2.40 and bought back in at $1.60 a few times and you are proud of your skills and wish you had done it more often. However, you might have sold at $2.40 and the share price then went to $3 and you never bought back in. Could you have really predicted t the time that your $2.40 sale was a short term peak and you could have bought back in for less? Or just felt you were right and, in hindsight, you were proven correct this time, but on some other share you were incorrect and lost out on the big gains.