Using a single cloud provider with a multiple region setup won't protect you from some issues in their networking infrastructure, as the subject of this thread supposedly shows.
Although I guess depending on how your own infrastructure is setup, even a multi cloud provider setup won't save you from a network outage like the current Google cloud one.
Hum, I'm not an expert on Google cloud, but for AWS, regions are completely independent and run their own networking infrastructure. So if you really wanted to tolerate a region infrastructure failure, you could design your app to fail over to another region. There shouldn't be any single point of failure between the regions, at least as far as I know.
Although I guess depending on how your own infrastructure is setup, even a multi cloud provider setup won't save you from a network outage like the current Google cloud one.