Was actually surprised that ETH had able to retain the no. 2 spot despite of having that high fee issue which had been sitted for a while now and still unresolved.
I am not surprised that ETH is still the top altcoin, I agree that ETH's high transaction fees and slow transaction processing are a big problem for ETH also with the delay in ETH2.0 upgrade also causing ETH is affected. But you will not find an altcoin that is more secure than ETH and the most decentralized of all altcoins. Recent altcoins trade off decentralization for cheap transaction fees and fast transaction speeds, this is unwelcome and goes against the decentralized nature of cryptocurrencies.
The biggest issue with Ethereum is that even though the network is decentralized because a lot of the hash power is scattered all over the world the issue is the control that a small group of developers has over the entire project.
Remember how the EThereum classic was created? Due to the DAO hack. They have too much influence and hence why many are still trusting Bitcoin more since Satoshi is a mystery and most likely he will never move his coins until the devs holding all that ETH from their ICO.