I'm unsure why this went so bad!

Is it as bad as that Ascot Jon

Not that bad but its about the same as that cryselco bc tube that took 2 days of running to revive

Is this reviveable?

If the voltage is so high, then most likely one of the cathodes has become disconnected, or the emitter is entirely consumed. I suspect the former. It has basically turned into a cold cathode lamp and needs a high voltage low current to operate.

I don't think it is the cathodes, they do the cold cathode glow on startup then the tube appears to brighten slightly and the purple glow goes. The voltage also drops slightly, so I think this tube is still running in hot cathode mode. Plus the lamp lights a deep orange until it warms up. What concerns me however is the impurities are not precipitating out yet.