It can be more than enough because the truth of the matter is that not everyone uses bitcoin. Not everyone needs bitcoin. And not everyone needs to have X amount because there's only 21 million. (I.e.) The homeless people in the streets dont have money... while it may be a nice gesture not all people share/donate or are obligated to share/donate their money...
I understand that there is a limited supply but not everyone has the use for them or even knows what they are so I think the bitcoin community is in a good position because we dont have to worry about not having enough