That's not the reason Cardano failed though. All the capital had already established itself on other platforms and "it uses a better language" wasn't enough of an incentive to switch. It's an overwhelmingly common story in that ecosystem, even with other networks that Solidity can target.

I don't know what it takes to write (or wire up) a smart contracts language, but when I, as someone past beginner level, looked up the Cardano docs on how to build contracts I was mega confused and had no clear way how to get started.