For Bitcoin, high transaction costs have made it competitive by Litecoin, XRP, DASH, BCH. But the LightningNetwork solution effectively solved this problem for El Salvador.
For Ethereum: high transaction costs have forced users to switch to BSC and other platforms. They are not willing to pay 100-1000 USD per transaction.
I hope the upcoming update of Ethereum will help reduce transaction fees and bring Ethereum back to its glory days.