Bitcoin already had a value, It just need people to believe on this technology's capability. It did reached the $20,000 level, and that time Bitcoin began to have a lot of people/followers who invested with the hopes of "getting rich overnight", or we call them the weakhands.
Though, the market has been manipulated by big players, but retail investors role is somehow vital for the future of Bitcoin.
Manipulation, speculations, and sentiments are the factors that drives the market value of Bitcoin.