Not really! One might argue diffusion models to be better but GAN and Diffusion both models have a reason to exist.

With diffusion model, you have a lot of room to play around with different types of data and change your architecture accordance to that data.

But, where GANs outshines, it's a model that's primarily used for tricky things as increasing resolution and more. Usage of GANs have been old-fashioned but there's lot to explore with GANs as it's a dynamic architecture, different from diffusion that's static.