What is the first principle of bitcoin?

Frances, is that you?

I have consider the possibility that you want to troll us with this post.

If Bitcoin goes 1 million per coin it means 1 Satoshi will cost 1 dollar. And Lightning Network already uses millisatoshis.

I think that is all unit bias and the idea of holding 1 of something is just a comfort that fiat provides, people will have to set used to having a fraction of a bitcoin or price things in sats. As satoshis increase in purchasing power, we may even need to fork in more decimal points to keep it practical to use mili satoshis and so it continues.

Owning 1 bitcoin is already more than most people can save in their lifetime around the developing world, and soon it will be too much for people in the developed world to own, they will get used to it the same way everyone else will

Owning a whole bitcoin will be like owning a building, very few will own it, but people will own parts of that building and it will all hold value

I am not sure what you're getting at. Bitcoin can be bought in other amounts that are not 1 whole BTC and you can spend in any amount you want. The price has nothing to do with peoples ability to spend. Even if Bitcoin goes to 100,000 million per coin, you will still be able to buy and use some fraction for some amount.