Which coffee pot are you talking about, the metal ones of the new automatic push the button ones? If you're referring to the metal ones where the attendant's actually made the pot of coffee, they didn't go away because they were too hard to keep them working. They went away for safety reasons.
If you're referring to the automatic ones, which were added later to replace the metal pots, those Amtrak is having a hard time keeping working.
Gosh, I seem to recall having more than just two types of coffee makers in the Viewliners over the years. Though, honestly, I wasn't keeping notes on model numbers, etc.
However, I do remember "metal ones" being there, but not working. Did Amtrak disconnect the "metal ones", but leave them installed for a while? If so, I could be miss-remember that as a broken (non-functioning) coffee pot.
I do remember once having a non-working coffee pot in my Viewliner, and attempting to use the coffee maker in another Viewliner (which I pass by, on the way to the dinning car). The attendant in that other Viewliner got extremely upset at me for daring to help myself to "his coffee". In all my years, that was the only time I had ever encountered a really nasty attendant. Hay, it wasn't like I was a coach passenger attempting to steal a fee cup of coffee or something.