How does it follow that because a cloud provider has downtime that self-hosting is a better solution?
Without numbers, I don't see how you can make any decent conclusion at all.
Is that all you have seen? I have seen many self hosted services fail in our company and the answer is almost rarely any of these simple things but complex things like data loss, data corruption, random restarts, network partition, configuration sync issues etc. That is why companies pay other companies for critical things like gitlab even when self hosting.