Don’t expect shares, re-posts, commenting etc, if you never reciprocate.
Social Media needs interaction. Unless you pay the same respect and attention to others who follow you or are members of your pages, they will never return the favor.
Especially professionals you have worked with. If you don;t care, nobody else will. Show you are respectful, show you know how to follow requests for sharing posts or information. By sitting idle and just posting your own stuff, nobody will care.
It takes a village. The more visibility you want, the more effort you have to put in by actually reading posts by others, commenting, sharing etc. And this goes for EVERY Social Media Outlet.
Having a lot of followers that you never interact with, tells the world that you are only in it for yourself.
So, in order to gain momentum and get where you want, show RESPECT to receive respect!