For me, the major reason Bitcoin is where it's today is because of the community. It's not even about its size. Bitcoin has got well structured and committed community. Nothing much else Bitcoin is doing that other cryptos aren't doing or even doing better and easier. Come to even think of it, there's no smart contract to Bitcoin like Eth and others have. It's a PoW and doesn't afford hodlers much benefit of earning more quantity on staking apart from price appreciation, unlike PoS where staking is allowed. Nevertheless, I still think it will be unimaginable for Bitcoin to fail. If it does, that will be the death of the crypto industry. The confidence reposed in this industry is garnered from Bitcoin. If Bitcoin collapses, the entire crypto market will disappear.