Earlier quoted context omitted.
There are different risks, but there is not necessarily more risk. Does Codespaces have lower or higher than the availability risks of your current environment?
My current environment is my laptop, which I would also need to access codespaces. So by extension, codespaces is more risky than my current environment.
It's certainly reasonable to think that a SaaS can approach availability time of a single piece of hardware.
Furthermore, it appears that engineering github/github to work in codespaces helped their local provisioning as well.