The emergence of so-called “Ethereum-killers” once threatened to dethrone Ethereum as the "king" of smart contract-enabled platforms. However, the network’s transition to proof-of-stake (PoS) may well cement its status as the de-facto blockchain for all things decentralised, which could render obsolete many of its competitors.
According to Arjun Kalsy, head of ecosystem at Mantle and former VP of growth at Polygon, what sets Ethereum apart now is not how scalable the Ethereum mainnet is set to become, but rather how familiar developers are with EVM (Ethereum Virtual Machine - the software that executes smart contracts).
Kalsy pointed out that assuming if the Ethereum mainnet processes 100,000 TPS (transactions per second) per day at 10 million users, the network will only be able to process 864 transactions per day, which means that the network is still not scalable enough if used by the masses. However, the reason why developers will continue building on Ethereum instead of other L1s is because of their knowledge of EVM.