There is no mathematical reason you couldn’t split satoshis in half or quarters or millionths. It wouldn’t change the hard cap, it’s just code allowing smaller units to spend. 1 BTC will always = 1 BTC, but that could also equal 1 billion nakamotos or some other sub-satoshi unit.

There will never be a consensus change to create more total bitcoin. There could easily be a future consensus change to further divide a satoshi as no current holders would be diluted.