Especially when houses like the Freys, Blackwoods, Lannisters, and Tyrells are so plentiful. It just seems odd that their family members are so few in number after all these years.
Maybe we just don't hear about all the houses that die out over the years, but most of the ones I've mentioned have been listed as old houses. Caron, Dondarrion, Penrose, Darry, Hornwood, and many other houses are teetering on the edge with only a few members left alive: Baratheon, Bolton, Tallhart, Umber, Stark, Arryn, Tully, Targaryen, Tarth, Florent, Velaryon, Serry, Greyjoy, and who knows how many others. Seems strange that houses which have survived for hundreds or thousands of years and innumerable wars are now dropping like flies.