Cryptocurrency development makes a whole bunch of arbitrary value-guided decisions during creation, all of these decisions have tradeoffs such that nobody has figured out a way to feature them all at the same time, or would they want to.

For example, bitcoin is fully auditable. Anyone with a copy of the bitcoin blockchain can review every single transaction in bitcoin’s history, and trace the flow of every last satoshi from it’s mining to today. This is because the developers of bitcoin place a high value on verifiable auditability and security. Conversely monero was developed for the purpose of being a completely untraceable, unauditable currency that still has a knowable supply. And ethereum was created in a manner that intentionally supported scripting, so that it could be used as a platform for novel applications and contracts. None of these primary features could be ported to either of the other two without breaking them completely, because of the deep programmatic implications of the requirements.

It’s not really a question of better or worse, but of use case. The fact of the matter is that the reason these three examples are the leading currencies for their use case is literally because nobody has yet been able to do a better job. And for bitcoin at least, at this point it’s security rests just as much in it’s wide adoption and interest as it’s design intent, so it’s unlikely that anyone ever will.