Bitcoin is an online currency. Even if started with a lower price. Now its value is beyond the reach of ordinary people. But, nowadays, it seems that Bitcoin is losing its popularity.Because, not receiving validity in low income countries. It may be the main reason.
What do you mean by "low-income countries"? If third-world countries is what you are talking about, I don't think it is a reason why bitcoin is losing popularity. Here in the Philippines, some universities already offer a course about blockchain technology. Some business also starts to adopt bitcoin as one of the payment. I don't even believe that bitcoin is losing popularity now because it has a big potential in our future technology.
I think so because as well all I know bitcoin coins are expensive especially to those poor countries. They can't afford to invest in it the reason why there are only a few people who are interested to invest in it in poor countries. Yes, there are many establishments now adopting crypto and the technology behind crypto also. In this case, many people will probably know about bitcoin because of the usage of it and how you become to gain profit if you are investing in it. Losing popularity is impossible to happen.