Under no circumstances will Bitcoin become a stable coin, though it can trade along a constant price over a certain period but it won't be term as stable coin. Stable coin like USDT is coins with a pegged to US dollar at 1:1 ratio.
As bitcoin not a stable coin people becoming more interested on investing on bitcoin instead of a fiat (usd, gbp etc), there are many reason of investing on bitcoin and not becoming stable is one of them.