I don't think it is necessary. Ethereum and Bitcoin have their own advantages. They are very good coins, but we can't predict the future of cryptocurrencies. Bitcoin may be defeated by Ethereum, or it may be one of the future. New coins are defeated, this is something that cannot be known.
The purpose of the discussion here is that ethereum can be the next bitcoin which is now the ruler of crypto with marketcap of more than 52%, all coins certainly have ambitious goals to replace bitcoin and become number # 1, if this happens it certainly becomes a good thing so it makes competition becomes more interesting.