So all RPGs should regard 5E as the sweet-spot for complexity and never go beyond it?That said, Paizo has had four plus years to study 5E and draw conclusions why it is successful. If they chose to not do so, that's on them.
No doubt the relative simplicity of 5E has played a part in its success. But the D&D market today is a big pie, and Paizo only needs a piece of it to be commercially successful. A strategy of retaining two-thirds of its existing customer-based and attracting the 20 per cent of the D&D customer-base that's open to more complexity may well be a better business decision than targeting the exact same market as 5E and hoping to distinguish yourself by, what - Golarion?