To expand: At $dayjob we use AWS, and we have no plans to switch because we're tiny, like ~5000 DAU last I checked. Our AWS bill is <$600/mo. To get anything remotely resembling the reliability that AWS gives us we would need to spend tens of thousands up-front buying hardware, then something approximating our current AWS bill for colocation services. Or we could host fully on-prem, but then we're paying even more up-front for site-level stuff like backup generators and network multihoming.
Meanwhile, RDS (for example) has given us something like one unexplained 15-minute outage in the last six years.
Obviously every situation is unique, and what works for one won't work for another. We have no expectation of ever having to suddenly 10x our scale, for instance, because we our growth is limited by other factors. But at our scale, given our business realities, I'm convinced that the cloud is the best option.