If bitcoin's price and market cap continue to increase, and if a 2nd layer or off-network protocol allows people to subdivide their satoshis into smaller and smaller units, does the whole 21 million BTC supply cap even matter anymore?
Dividing Bitcoin does not mean increasing it, it's always be capped at 21M.
To own 1 BTC, you need to buy 1 BTC
To own 0.1 BTC you need to buy 0.1 BTC
To own 0.01 BTC you need to buy 0.01 BTC
...
Dividing into smaller units does not mean increasing supply.
There are many on Twitter confusing it:
https://twitter.com/_benkaufman/status/1343839142287990784