We can see these days that not all people know cryptocurrencies, if they do perhaps they have heard only about bitcoin, but without owning or having the experience of making any transactions.
Maybe altcoins will become popular within 3 years from now?
Yes, it will take at least three years. On the one hand, ICO projects have evolved over the years and after some time they will start showing themselves. On the other hand, while the Altcoins will not give real results in practice, improving our lives, until then, people will not pay special attention to them. Therefore, another three years and will pass.