Great thought to ponder! I'd contend there's still some long-term value in legacy crypto but it's a much messier picture these days. The influx of capital into legacy crypto from speculators and institutional investors, plus the introduction of futures trading contracts, has created a market environment that's at risk of straying from the legacy crypto's "true" market value. Folks are also monitoring legacy cryptos that their tends to be an overcorrection with every technical movement.
I'm admittedly still long in ETH because I see some business value in the product, but have also started to spread my portfolio amongst the new, shinier alt coins.