I think it was not a technology that should have been designed for people actually doing series work. But for things like kiosk, self service terminals, and stuff like that.

And yes of course, a rack of commodity servers should how powered the server side, as this was a task that could be scaled vertically quite well.

The also didn't use the cheapest possible Sun Ray terminals, they used their internal developed embedded Sparc chip, not mass produced ARM chips.