I think that if bitcoin does not scale, it will dry out as with any technology/company that does not progress into the future, it will be replaced and forgotten, but for that to happen the community has to let it die, which I do not think will happen because btc is decentralized and have very committed fans.
Scalability alone cannot kill Bitcoin although it is good for it to scale in order to achieve the daily usage of BTC in the purchase of goods and services, thus serving its first purpose as a currency. If BTC does not scale, it will still remain as a store of value which is already seen now - due to its limited supply, the increase demand will raise its value which will bring more profits to its investors/holders.