That's apples and oranges. With RAID the server is never retired and you don't need to set up auto-scaling and all the scale-out complexity that comes with it.

That's apples and oranges. With RAID the server is never retired and you don't need to set up auto-scaling and all the scale-out complexity that comes with it. It just keeps running. The replace/resilver cycle may degrade performance whilst the data is re-replicated, but bringing up a new VM will also degrade performance for a while whilst it replicates data from some other node onto itself.