A friend of mine is not interested in buying Bitcoin even after learning about it.
Because according to him Bitcoin is a small number of people who have a lot of Bitcoin. They can easily go down on the bitcoin market if they want to.
First of all, there is no need to force any one to join Bitcoin investment or trading. If your friend isn't interested, it is okay. It means your friend is still not sure about Bitcoin and he doesn't understand the advantages of Bitcoin. He may already learn it, but he misses the part of the potential of Bitcoin in the future. Anyway, even if it is true that there are few people only who have a huge number of Bitcoin, it is never proven that it can destroy the market. We already experienced it for many years, and it doesn't influence much to the market activity. It is just his own assumption because he still doesn't understand enough about Bitcoin.
I agree with you who don't like investing in Bitcoin because they don't know how to make a profit from the investment they make with Bitcoin and they also won't be able to learn about Bitcoin because they don't like it or they already know an easier way to make money easily.