Not possible I think Bitcoin will always be the main currency. ETH was doing good breaking past 400 so quickly but, as soon as BTC got dumped (about $1000) ETH too fell sharply with bitcoin.
Of course, Bitcoin will still have to keep its leading position. But sooner or later, it will be replaced by a new technological coin that will topple Bitcoin from the pedestal. Perhaps it will be Ethereum, or perhaps a completely new coin.
It didn't happen for the last 12 years, so why will it happen at all? The creator of Bitcoin is anonymous and there is no individual or a group of people behind the blockchain and controlling the supply. On the other hand every other crypto project no matter what promisses, is backed up by one individual and his friends. Sooner or later he will leave the project or simply die, leaving his project to a sudden or slow death. Everything in defi is pump and dump tokens. It looks attractive to the n00bs for quick profit, but they don't realize that before cashing out their profits they will be gone, replaced by huge losses. One of the last tokens in defi - Sushi is the last example. For few days it gained a lot, then it's creator cashed out, leaving in dust and ashes all n00bs lured by the pump. This was the fate of bcash and it's clones whose creators were delusional that they will flip Bitcoin. Ver, Wu, CW, the list is endless. If you want to make money, you need to learn how to hodl Bitcoin for an extended period - 5, 10 years and more if necessary. The basics are solid and the risk is even lower than investing in stocks or fiat, which will lose due to inflation their value. The fast profit is for gamblers, with guaranteed loss at the end.