

I think it will be sooner than people expect. For at least 9 years now the US has not only been crumbling, but flailing as it does so. The ability of BRICs to shrug off the US actions is new and will have massive impacts soon.
BTC won’t be used as a currency IMHO. Blockchain likely will, but EVM is much more compelling. BTC might remain as a historical backing, but its trade will move to the ETH chains as well.

Position sensors exist - I had a Roland organ module years ago that had what they called a DBeam one. Basically a position based effect pedal.