If that happens btc will be no longer used for payment or any transactions, even though it's still an asset. We all know that people are using btc as investment and so if it never scales, other users or investors may stop supporting it. It will maybe lead btc fo fall. Also, even though other coins already exist, btc is still on demand and mostly use everywhere. Today, money keeps rotating on btc and alt coins, eventually if blockchain continuously grow, many coins will be generated and former coins maybe replaced but btc will stay. The value of btc is very important to us for it dictates our gain and income. It is also where our investment depends on.