So far more then 19 million bitcoin exists now. It's current price at the time of writing this is more then a 100k dollars.

Many people predict bitcoin will reach 1 million by 2030.

If it's true then many people will be millionaires. Many people had bought bitcoin when it's price was very low (many years ago) , so they could be owning a lot of bitcoin that would make them rich.

However a lot of people predicts bitcoin will never reach 1 million due to its stability. However there is a chance they could be wrong.

If bitcoin reaches 1 million then it can affect this world. Many people who got billions of dollars could buy every expensive things or fund researches. People will also switch to using crypto as payment. A lot of governments would have to regulate it and tax it somehow.

The richest person who invented bitcoin would be Satoshi Nakamoto, as he has 1 million btc in his wallet.