My question is that is it possible for everyone to have bitcoin with the number of limited supply of bitcoin ?
Of course, this is unlikely to happen with the limited amount of supply that has been set. And another reason, Bitcoin is not a legal currency so most governments still have rules if Bitcoin cannot be used as a legal means of transaction.
Yes, currently there are still many barriers for people to access bitcoin. but in the future, when it is recognized by the government and they are common to the people, everyone can access bitcoin. although it has a rather limited supply compared to our world population, as many others have said, we don't necessarily buy 1 bitcoin, we have one unit of Satoshi. so in my opinion, anyone can own bitcoin, but the question is whether they want it or not because to get bitcoin, we need money.