Unfortunately (and I say unfortunately because I like other coins too) ETH is not only there because of the first mover advantage. It is there because projects still prefer ETH and mainly ERC20 to be published. That is the big reason why ETH is still at second spot. Doesn't mean that it will never lose that position, we have seen plenty of projects lose that position but that doesn't change the fact that we are talking about something that is totally different reasoning then people expect.
As long as new projects keep getting listed in ETH and they keep getting popular, other projects will want to get listed there to be popular as well and that is the main reason why it is second. If projects slowly start to get listed in other networks, which already started but not growing fast enough, then we will see ETH getting to a lower rank one day.
Most projects prefer ETH because it's the oldest smart contract platform in the world. With a solid ecosystem of dApps, tokens, and services around it, ETH is too hard to ignore by mainstream developers and individuals alike. I guess no competitor can beat Ethereum no matter how fast and cheap they claim to be. Decentralization and censorship-resistance is what matters above all else. With ETH's PoS upgrade on the way, the main Ethereum blockchain will only become better over time. This will greatly solidify ETH's position on the market.
At least, gas fees won't remain high on ETH forever. Things would've been worse if fees kept rising without no indication of going down soon. As long as developers establish a balance between scalability and decentralization, there should be nothing to worry about. Just my thoughts