it's true that the number of bitcoin wallet users is still very small, but I strongly believe that number will increase over time.
Yes the numbers of blockchain wallet users might be small now compared to the global population and also there are other popular wallet providers too like coinbase, paxful etc nevertheless there is growing awareness about bitcoin everyday we have new entrant and investors coming on board to invest in cryptos I am very optimistic in few years to come the demand for bitcoin will grow in leaps and bound thus exceeding the numbers of present users.