Something to encourage new Argosy buyers: we fired up our 40 year old Dometic...
I have a '74 Argosy with the original A/C and Dometic refer. They still work. I did do some repairs on the Dometic. The safety shut off went bad and would not shut the gas off when a flameout occurred. I found a new safety valve online.
Replaced it and completed some needed maintenance on the burner and all is well. I did replace the heating element 4 years ago.
My guess is that there won't be one of these fancy " electronic" units running in 20 years. Let alone 40.