The Website is Messy, Patient's Don't Know Where To Look
If your website doesn't communicate clearly, or make your visitors feel comfortable, why would they trust YOU to make them feel that way?
Clunky, Slow, Outdated.
If your website looks old, that make's your practice look old, old = untrustworthy.
They Don't Rank on Google
Even if the site is amazing, if nobody sees it, it's a liability.