What are your thoughts on claims that the Ethereum network isn't sustainable and that it's smart contracts will be overtaken by networks like the Tron Network, Cardano, EOS? Surely Ethereum 2.0 should help?
We can't be sure unless we see that ethereum 2.0 on live.
There's nothing wrong if another network will overtake smart contracts if it can't really sustain itself. The only constant in this world is change and that's why if there are new things to be discovered and being liked by the people then it shall dominate.