Fame is part of it, but it's more that it's IMO probably the only truly decentralized cryptocurrency. Not just in terms of the nodes and miners being well spread out between organizations and parts of the world, but also in terms of its development and governance. Sure, there's a relatively small group of core contributors to Bitcoin, but they don't have much fame or personality cults around them like Ethereum's Vitalik does. They are really just restricted to maintaining and adding well-agreed-upon new features to Bitcoin. Eg when Segwit happened, a lot of miners held out on supporting it for a long time becasue it was a bit controversial. Meanwhile with Ethereum, if Vitalik really pushed for some controversial change, it would probably happen. Once you go further down the list than Ethereum, things get really bad, with many cryptos' development being entirely driven by a small group of people in a for-profit company, with miners and users that will blindly update to the newest version regardless of what's in it.