What a slippery slope. I imagine a future when the entire URL itself has disappeared and we live in some sort of Google-controlled walled garden environment, like what they're trying to do with AMP[0]. Some sites only work with WWW prefixed as the APEX DNS record is misconfigured and points to nothing. I've even seen some sites point to `0.0.0.0' but had a CNAME record for WWW and I could then view the site.
[0] https://developers.google.com/amp/