Bitcoin is whatever you want it to be, and that's the beauty of it. It's true that it is nowadays mainly used as an investment, but it is still efficient and cheap way (if you know how to manually adjust fee) to transfer money, especially bigger amounts. Bare in mind that Bitcoin is actually still new, ~decade is nothing for something disruptive like this, and sooner or later some solutions like LN will make it more cheaper to transfer.

So no, I don't think that Bitcoin lost its purpose.