That's really not true. You'll find a lot more people with no bank account than you will with no internet access at all. Many of the poorest in the world still have at least a cheap cell phone with some internet access.
There are actually "unbanked" Africans, according to this article they just use their mobile provider's feature of credit transfer to bank that way: https://archive.ph/imZOj - it allows them to buy and sell things and settle debts by transferring digital money between phone numbers.
But probably not good enough for the crypto-bros, it's a centralized system!!1!!