I'm genuinely curious: what exactly is so hard about installing and system administering one's own servers inhouse that so many people would put up with these complications?
There isn't any true difficulty; people are running multiple sites that could all fit into 1 dedicated 64gb RAM server from Hetzner on a different infrastructure that allows them to develop their resume...
For us its: availability outside of VPN and avoiding the run around of making a public site with security, integration with active directory, has repos + a wiki + boards all in one place. No configuring 3 different OSS products to integrate with AD.
We use the other stuff more than the CI, but will probably begin using it for some more smaller projects soon. It'll be in the same place which is great and no need to tinker with servers which is awesome.
Or AD isn't our responsibility and we can just use the tool (Azure devops) that is already done before we even launch it and provides all the features we need?
I guess you don't have more important things to be doing than screwing with ancillary tools.