Ouch! What a terrible, random thing to have happen. It is so sad to see it happen to something so historic on top of that. I almost can't believe the news...it feels like only yesterday that I saw it come to life for the first time in ~60 years, and now this.
I hope that the RACS repair idea is successful.
It could be the heat wave.....one of the replacement PS doubler caps I installed in my Silvertone roundy almost 2 years back went bad 11 days ago, and that was a fairly robust part! The year before I left the air conditioning off during vacation and returned to find one of the plastic feet on that same set had shattered despite the set being left otherwise undisturbed.
It might be a good idea to add some fans to the set if you ever get a good CRT in it again.
Life sucks sometimes.......