Bitcoin won't be worthless in the near future. Bitcoin is already accepted as a payment method by leading companies as well some government agencies. Since there is a limited supply of Bitcoin available, price won't be worthless. Personally, I believe that the only reason its price can go down in the future will be rise of new cryptocurrencies with better technology, capabilities and decentralization. Imagine if altcoins such as Ethereum, XRP, NEO, TRON are not existing now, Bitcoin could have a higher price than it's current price in my opinion.