Long-term I don't think you should need any JavaScript! Unless you're using the web for "apps" I disagree with.
Short-term... I think this is already the case for most webdevs! Even if the industry appears to disagree!
@alcinnz I encountered a website implementing it's own loading animation yesterday, replacing the browsers own with no improvement in functionality. This was a pretty traditional webpage, not an app.
Why?
@LovesTha I blame accidental collusion between educators teaching what gets people hired, & recruiters hiring on what gets taught!