Comment by bborud

To a greater or lesser degree yes, but there are things you can do to safeguard your business.

I don't think the biggest risk is really your hosting environment, but domain names. That's the one link in the chain that can really make life miserable if you were to lose your domain name. Which in effect is your identity. You can find replacement service providers for hosting. It may take you a bit of time to move things, but there isn't a lack of choice. It is harder to deal with losing a domain name that is essentially your brand.

However, I know several businesses whose product only runs on AWS and would need a ground-up rewrite to run anywhere else. Not to put too fine a point on it, but that is exceptionally poor risk management and if I were to find myself in this situation I'd have nobody else to blame but myself.

And this is transitive: if you are a customer of a product that is tied 100% to a single infrastructure provider and they are critical to your business, you must have a contingency plan in case they get into trouble.