Depends on what you mean by "just Moore's law." Certainly each standard was developed with a higher target decode complexity; H.264 and H.265 both targeted 2x greater than the previous standard, JVET is currently targeting 16x, and I think AV1 is aiming for less than 2x HW area.
So yeah, there were obvious gains left on the table for H.264 for complexity reasons that H.265 picked up; likewise for H.265/VP9 that AV1 picked up.
That said, there has been a lot of refinement that didn't necessarily increase complexity, and there have been various tools that saw reinvigorated research once complexity targets were raised.
So yeah, there were obvious gains left on the table for H.264 for complexity reasons that H.265 picked up; likewise for H.265/VP9 that AV1 picked up.
That said, there has been a lot of refinement that didn't necessarily increase complexity, and there have been various tools that saw reinvigorated research once complexity targets were raised.