Volatility describes how far individual results scatter around the average. It is the difference between a game that grinds and one that lurches, and in Plinko you set it yourself.
Imagine two settings, both returning 99% over the long run. The first pays between 0.9× and 1.2× on almost every drop. The second pays 0.2× on most drops and 500× on rare ones. Play a hundred rounds of each and the first will land close to where you started; the second will usually be far down, occasionally far up. Same expected value, completely different experience.
That is the whole of what risk level does in Plinko. It never improves the return — it decides how the return arrives.
More rows means more slots and a wider gap between centre and edge multipliers. Sixteen rows on high risk is the most extreme configuration most implementations offer: the great majority of drops return a fraction of the stake, and the headline multiplier sits behind odds of roughly one in sixty-five thousand.
It shortens it, unpredictably. A balance that would last a thousand drops at low risk can be gone in fifty at high risk, purely through ordinary bad luck rather than anything unusual. This is not a flaw in the game; it is the arrangement you selected. The mistake is choosing high volatility while expecting low-volatility behaviour.