Does counterfeit and genuine fashion is the same?

I mean, i recently red articles how to spot fake lacoste shirts but in my experience i have bought shirts (topman, puma)from loyal high street shops which soon after that ending up in bad quality. is that might be true that fake and genuine shirts are being produced in the same factory or in seperate factories with the same quality requirements?
Answer
Fakes tend to be less quality and poorly copied so spend a little money on quality