A lot of the design decisions seem to prioritize expressiveness over performance, with the type system and multiple dispatch etc. If they wanted a performant python, they wouldn't have made those choices. So clearly they think Julia is good in other ways, but it didn't make the marketing pitch, which tended to be just 'performant python'.

Now Mojo's going to come along and probably fill that niche, which might at the very least force Julia's community to focus a bit more on its other advantages.