For example I discovered bitcoin, I will not show myself and tell that I discovered bitcoin because it will make my life risky and I can't make a life that I want too. Its the same with the creator of bitcoin. He/She or They will now show his/her or their true identity because they don't want to risk their life. Bitcoin is very popular nowadays and with its high price and if the creator shows in public, many people will go and try to do something bad.