To be fair, most of Dr. Phil's viewers lack either the maturity or communication skills to maintain a polyamory lifestyle. Everyone who comes on that show with relationship issues has a lot of baggage to deal with. People who haven't even learned to maintain a single, healthy relationship have no business trying to bring more people into their problematic world. So to that end, with regards to most of his viewers and virtually all of his guests, he's right that polyamory is unsustainable and not a good idea.
Overall, I've found that Dr. Phil's advice comes in two flavours: blatantly skewed, and blatantly obvious. Much of what he says is total common sense, but I tend to forget that common sense is anything but common.
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker