If we model the stock market as a random walk/Weiner process and I got the math right, I think you're almost certainly going to make money (if you stop when you reach a given profit threshold), but you will have arbitrarily large drawdowns. This is similar in terms of the risk/return profile to the martingale betting system. https://en.wikipedia.org/wiki/Martingale_(betting_system)
Most games I play have pretty steady ping. I am doubtful QoS would decrease ping a lot.
> If you want to observe this effect then try turning QoS on or off on your router during your wife's Netflix session while you're playing a multi-player RPG.
That's because the network is congested and Netflix keeps trying to push as many packets as possible, hence your game packets may not reach on time. But, placing a simple bandwidth limit on other devices is enough to ensure proper ping for your game.