The 200 day moving average has no physical influence on a stock. But if enough capital places buy orders near it, orders exist, and price can react. The same argument applies to round-number-levels, the golden-pocket and widely published pivot-point levels.
This is a genuine mechanism, and it explains why the most-watched levels on the most-watched instruments behave differently from obscure ones. It also predicts something testable: the effect should be stronger where attention is concentrated.
It has limits that are often ignored. Self-fulfilling effects are small relative to real order flow, they break instantly when information arrives, and they can invert when everyone positions the same way, which is exactly the setup for a liquidity-sweep. Attention creates orders; it does not create demand.
Related: moving-average-as-support, round-number-level, liquidity-sweep, golden-pocket, technical-analysis