We saw Lightning try and solve that issue with Bitcoin, but it's just a band aid on what is quite a slow and clunky blockchain.

Why is it a bandaid? It allows native bitcoin transactions instantly and the liquidity and merchant adoption is growing constantly. Similarly to our current monetary system, it functions and scales in layers (VISA transactions settle later with bank transactions). It's impossible to make a globally adopted crypto that would allow fast transactions on the base layer for the whole world while at the same time maintaining decentralization. That would bloat the blockchain which would leave only enterprise level entities being able to run a node. Slow base money on the bottom, and payment systems on top of that.