one thing about technologies, specially new ones is that they spread very fast. their adoption curve is usually like an S curve and in case of bitcoin this is very true. and the characteristics of an S curve for adoption is that it is pretty slow at first (like the past 9 years) then it slowly speeds up and finally becomes so rapid that it reaches its final stage in a very short time hence creating the vertical part of the S curve.
How many years you think are still left in the slow phase ? The length of S curve can vary a lot in between different technologies. For instance, let us talk about Facebook. Facebook is now 14 years old and I think that initial phase of slow adoption is already over for it. I think it has reached 90% of its potential already in terms of user base and it is now very hard for it maintain this number. Facebook is something that people are able to use without the fear of losing any money. In case of bitcoins, this is not true.