I'm not sure that's the real problem. Good firms just try to have the best people in their roster (best creativity and skills). These designers have the same ap

I'm not sure that's the real problem. Good firms just try to have the best people in their roster (best creativity and skills). These designers have the same approach a single person would have: figure out the company's identity and come up with a solution that represents it best. On average, you would probably get better results by hiring a firm than a single person. I suspect the real problem is related to the ongoing simplification trend that logos have been through for the past decades. Take apple's or pepsi's logo for instance. This minimalist trend results in simple shapes, and there is a finite number of simple shapes out there. So when designing a logo according to this trend(as everyone is doing and have done in the past), you will probably end up with something similar or equal to something else. Not many dimensions to play with. (Sorry for my English)