I don't think that Bitcoin will be relevant after 5 years from now. It is the most popular cryptocurrency. I am not sure if Bitcoin could integrate advanced crypto technologies like Smart contracts, DApps, etc. within its ecosystem.
A possibility is there that it will release another cryptocurrency backed by Bitcoin which will support advanced technologies.
I don't consider Bitcoin the best investment, not because its value has fallen down below $10,000. It will rise again, but there are other promising cryptocurrencies that can shoot up in the stars within the next 2-3 years.