Search engine optimization is now mainstream no longer the domain of a few professionals who annihilated everyone in the industry it is now a specialist subject taught in colleges and courses around the world. These people teaching these courses maybe good well at least one or two of them however seo experts who have perfected their craft recognize nuances that these professionals will never know as we have learned as we have gone along and shared this knowledge with each other.
The modern seo expert consists of someone who has learned a few basics seen a little success on one or two websites and shared this with their team full stop. These people will find it impossible to reach the level of seo expertise that the top people in the industry are capable of.
That is why I always recommend you forgo the expert at the development stages of your web presence and build as you go along only when you are sure you can go no further should you consult one of the so called experts of which 99% are anything but.