I don't understand the smart contract "wars"

Hello everyone,

I've been in crypto for couple of years and I don't understand all the Smart Contract blockchains and their advantages.

I understand what is a smart contract, and how they work, but why do we have a new top 10 smart contract blockchain every 1-2 years??

All of them say: Faster transactions, Cheaper transactions, More Security. What is their other advantage than a fancy website with promises, compared to other projects??
I do not understand why Ethereum is still the dominant Smart Contract blockchain. And for the same reason I don't understand why Ethereum is not 95% dominating the Smart Contract market.

Please educate me. Why do we need 50 different Smart Contract blockchains. And what is the overall advantage of Etheum, that it's still the number one Smart Contract blockchain