You said "The 0.0001 BTC on each physical Bitcoin will be too little to use, " but does it matter what the value of that bitcoin will be in 10-20 years, or will the fee to send also increase at the same rate as the value of bitcoin? A particular amount of BTC dust will always be dust even if 1 BTC = 1 Million USD?
Nobody knows

But 10,000 sat means there's nothing left if you use just 90 sat/byte fee. Fees have been 10 times higher than that. But by the time it's worth $100, I can only hope fees won't be $100+.