Yeah, that's not what that means at all. When you're on a dedicated instance, your greatest enemy is no longer the data center or the company you rent from, but it is yourself, and you'll probably be the biggest cause for any downtime as the hoster will leave your instance alone for as long as they possibly can. If someone goes wrong, you usually have access to support that can physically reset it for you and they'll do it quickly. Dedicated instance also doesn't mean with redundancy, so you'll survive with one or more instances down for some period of time.

But you don't have to trust me for it. Check what kind of uptime famous companies like Hurricane Electric Vultr or Hetzner typically have so you could update your outdated view on dedicated hosting.