The value of bitcoin depend on a lot of things the most important one would be how much people know about it and invest in it and trust it a lot of people because we all here want to have some bitcoins and that is already a lot of people.
Just investing on bitcoin won't help the price to increase. People will need to adopt it. They got to use it as a medium of exchange rather than using it only as a storage medium. The more it is used, the better the price will be.