Bitcoin doesn't have decimals, it has sats. "Whole coins" are an abstraction, a Bitcoin is 100M base units, sats. You can't add abstracted decimal places without a supply increase of the base unit, which would break every piece of Bitcoin software ever created... it's not going to happen. 2.1q sats -> 21q usats or whatever is a 10x supply increase. The hardest fork imaginable.