The problem is not with the services itself it's more in regards of infrastructure, backups etc. If you run the services yourself there is not a single point of failure as you would have with a SAAS.
Also team considerations. When you add an important moving part (all your devs will complain bitterly when it breaks and their work will be significantly impacted) you need at least 2 people who know how to keep it running at a minimum, and more would be better.