If an enclosure fails before the drive that would seem highly unusual to me.
That sounds reasonable as respects a HDD, because its moving parts and coated platters guarantee that it
will fail sooner or later, while a SSD may
never fail, leaving the enclosure's components and assembly the weak links in that, i.e. my, configuration.
I located my purchase date (good idea, thanks), and since I bought the enclosure (1 year warrantee empty...3 years with any drive inside) almost 3 1/2 years ago and installed the SSD (10 year warrantee) a year later, it's not at all surprising for the enclosure to have failed first (and presumably within OWC's more or less expected time frame).