What they pioneered isn't the seed accelerator concept, but rather a repeatable model for it. It's the difference between the idea for a burger bar, and Macdon

What they pioneered isn't the seed accelerator concept, but rather a repeatable model for it. It's the difference between the idea for a burger bar, and Macdonalds developing a franchise model for it. YC have always stated that there can be only one YC and that's the global YC. TechStars have the position that they can design a playbook that allows their "magic sauce" to be replicated. Although they should (as they have done in the past) acknowledge YC's inspiration of their model.