Back in the days before cloud computing, it used to be accepted (if somewhat resented) by management types that having redundant systems in place was important if you cared - even a little - about uptime.
In today's industry, those same management types generally understand that it's still important to have multi-region availability, with instances running in completely distinct provider regions, so that an outage in one area doesn't impact your ability to do business.
What doesn't seem to be quite so widely understood, or accepted, though is the importance of ensuring that systems have redundancy across providers. It's not just management types who are making this mistake either, we've all encountered techies who are seemingly blind to the risk and view it as an un-necessary additional cost/hassle.
Rather than typing "the provider" throughout this post, I'm going to pick on AWS, but the argument applies to all Cloud providers.