Bitcoin is technically for both the rich and the poor. While you can buy small fractions of it, such tiny amounts cannot usually be used to purchase bigger things. In practice, cash is still required for such transactions. Therefore, it’s not entirely accurate to say that Bitcoin equally serves both the rich and the poor.
Bitcoin is an asset and the longer you hold it, the more likely you are to make a profit. Rich people have a much higher income than poor people, so naturally they can accumulate more Bitcoin stacks, so they are more likely to make a higher profit. It will take longer for poor investors to accumulate the amount available. If it takes one or two cycles for the rich to get a decent holding, it may take longer for the poor.