I didn't think you could kill a Dendrobium, they even seem to be stronger than my Cattleyas.
I used to be more down on dendros than lately. I found that there are a few I can grow (if they are minis like D. aberrans or D. senile or deciduous like D. anosmum.) Phalenopsis type are just too finicky for my tastes. They usually just up-and-die for me