Let's consider the following scenario: The world is 2100, everyone is using bitcoin as a global money and all prices will be expressed in bitcoins. It seems obvious that in a scenario like this there will be just a few things that will be priced in bitcoin and have a value of 1 BTC. Most of the goods and services that will be sold then will use maybe satoshi as the currency that they will be priced in. And there could even be the need to go even lower, and price things in milisathosi's.

But being a digital money, there could be a protocol upgrade to support more than 8 decimals, so that you could buy a cup of coffee or something. If such an upgrade occurs, isn't it akin to an increase in the money supply by a factor of ten (in the case of one more decimal)? And continuing our train of thought, in another 50 years when the economy will be even more productive, you will need another decimal for small transactions. And so you can basically inflate the money supply ad infinitum, based on the "needs of commerce".

So, to sum up, being able to divide the bitcoin in ever smaller denominations, isn't this a way to inflate the money supply?