The main difference is the ecosystem. The Haskell community has always focused primarily on the computer science part, so the developer experience has mostly been neglected. They have been unable to attract a large enough hobbyist community to develop the libraries and tooling you'd take for granted with any other language, and no company is willing to pay for it out of pocket either. Even load-bearing libraries feel like a half-finished master's thesis, because that's usually what it is.
No amount of advertising is going to propel Haskell to a mainstream language. If it wants to succeed (and let's be honest, it probably doesn't), it's going to need an investment of millions of developer-hours in libraries and tooling. No matter how pretty and elegant the language may be, if you have to reinvent the wheel every time you go beyond "hello world" you're going to think twice before considering it for production code.
No amount of advertising is going to propel Haskell to a mainstream language. If it wants to succeed (and let's be honest, it probably doesn't), it's going to need an investment of millions of developer-hours in libraries and tooling. No matter how pretty and elegant the language may be, if you have to reinvent the wheel every time you go beyond "hello world" you're going to think twice before considering it for production code.