Bitcoin is the most secure blockchain because of it uses Proof-of-Work. The fact that a ledger exists that takes hundreds of thousands of dollars to even attack a signal block is valuable. The security of the underlying chain is solid as opposed to chains that compromise that security for speed. Sure the Bitcoin protocol can't be used for day to day transactions, but it's integrity as a ledger is unparalleled. But it is easy to understand why most regular users would overlook this property.

Ethereum is overly complex and complexity stifles long-term innovation. There's a reason that Ethereum 2.0 has taken so long to develop and has experienced lots of delays. Scaling blockchains is a yet-to-be solved problem. I honestly think some other coin is more likely to overtake Ethereum before Ethereum takes over Bitcoin. That's not to say that Ethereum doesn't have more upside than Bitcoin, but my experiences with complexity give me many doubts about its ability to grow and be maintained.

Most native Proof-of-Stake coins have centralization issues. The Steem-Hive debacle shows how little security some of these coins have. A lot of ICOs and coins of the last bull run have shown little real innovation and have shown themselves to have used the marketing first and engineering second approach. It turns out that building blockchains is really hard and such approaches typically never meet expectations. People have been attempting to do stuff like this since the late 1980s. The technology has so much more nuance around it than simply whether or not it makes it easier to buy something online with. I appreciate the experimentation of other coins, but I haven't seen the technology that makes Bitcoin obsolete yet. I could be completely wrong, but my experience in the space over the past three years has strengthened this viewpoint rather than weakened it. Should be interesting to see what the future holds though.