Putting all your eggs in one basket doesn't always work out well. We've all done it, and when done in a business context (e.g., Cloudflare's July outage that briefly tanked numerous web-based businesses), the consequences can be far-reaching and dire.
It's way easier to keep everything all in one spot. However, just because it's easier doesn't make it more beneficial, nor does it make it better.
Cloud computing has suffered the wrath of convenience. Sure, it might be more convenient in management and contracting to consolidate cloud resources to a single provider, but you might experience a variety of losses in doing so. These losses may be in actual costs, but more likely, they're the result of sacrifices in not immediately fiscal areas.