Generalize much? That statement could not be less true. Many of the worlds best wildlife photographers were still using 7D's as recently as a month ago, That was when they switched to 7D2's. You should get out more or find some new "professional" wildlife photographers to shoot with.
I've been shooting with the world's best in Montana the last three months, and none of them would use a 7D or 7DII as a doorstop.
The sensor is ancient tech.
Canon's high MP, APS-C cameras are great for situations where you control the light, such as fashion or portrait. But when filming wild animals during winter inversions, they're just not up to the task. FF is.