“Your own server in a colo” means going to the colo to swap RAM or an SSD when something goes wrong. You rent a server and the benefit is the rentor has spare parts on hand and staff to swap parts out.

So on average once or twice per 5 years per server. Remote hands are also service you can pay for.

Most expense is initial setup and automation, but once you get thru that hump and have non-spiky loads it can be massively cheaper

You can also pay smart hands to do that. My experience with Equinix for example it's been great.