There are many reasons Bitcoin is likely not usable in the real world at scale. It's important to understand long-term value vs short-term speculation. Interestingly, many cryptos are built on the Bitcoin blockchain, and include additional benefits Bitcoin lacks, like Proof of Stake (instead of Proof of Work) and block size.
That being said, it's all about supply/demand. What are people willing to pay for Bitcoin? When people realize that Bitcoin isn't the /best/ technology, the value is likely to stop growing.