I'm sorry but you're dead wrong about the BMS. BMS doesn't address any of the things I listed.

You're also wrong about standardization - standarization at the cell form factor level is correct. Different applications have different capacity vs power density requirements, temperature range requirements, cost, lifecycle... a pouch cell that goes in a drone looks a lot like one that goes in a cell phone but they're optimized for completely different workloads.

Also we already have standardized interfaces for external batteries with most power banks using USB-C, so in a way your wish has already come true.