Digital yuan will most likely not be managed by a business. I assure you that the Chinese government will not be outsourcing critical components of their digital currency network to such companies without serious oversight and review of each patch made.
I speak of a custom-built mainframe with a custom-built kernel (though probably forked off Linux). These cannot really be compared to some servers run by people who simply purchase solutions from other companies. There is no room for "let's outsource this without oversight" when it comes to building a digital currency.
There is much reduced possibility for failure when there is only one vendor for the software, and only one hardware that the software must run on (even better when the software and hardware are made for each other), and the government is standing over the shoulder of the singular vendor to make sure everything works.
Anyways, back to AIX as an example of a robust custom-built kernel: AIX mainframes have not had a serious failure in all the years they have served as the workhorse of the global financial sector. I think that is a good enough rebuttal of "we can't have a digital currency because the servers might fail".
