heres my take on it
what you need to understand is that if all the variables could be measured in the flipping of a coin, one could theoretically calculate what side a coin would land on. Similarly with a roulette wheel, with all the forces taken into consideration, one could calculate the exact number the ball would land on. but the fact of the matter is that there are far too many changing variables that cant be precisely measured (not easily anyway). My point is that probability (as we understand it) is an abstract concept, it doesn't actually exist. it is only what we perceive as probability.
With that said, the direction that a stock will go in has far simpler observable and measurable variables acting upon it. those variables being the psychology of the traders involved, volume, sentiment of markets etc. This gives an oversold or overbought stock the tendency to retrace (depending on the s sentiment of the market, futures, volume, and so on)
On the other hand
bingo balls popping out of the machine have a continuously varying air stream. imperfect walls (creating further varying turbulance and affecting the direction that balls will bounch off of), imperfect balls,, etc you get the point, but you better believe that if it were possible to measure all those variables and surfaces down to the atomic level, one could calculate which balls would pop out and in what order.
my point is that a stock is often easier to predict than a coin. We only say a coin is random because we are unable to measure all the variables
I think it could more likely be compared to a tug of war rather than tossing a coin. with a tug of war, although not always, one can gain a sense of whose going to win. There are more easily observable variables.
in the end i think that you as an experienced trader has a better "probability" of winning while attempting to buy at the bottom than an inexperienced trader not knowing better always buying in an overbought situation.