Sub-Menus without dropdowns

Is there any way to not use the drop down menus, and rather have the primary menu show the subpages/children of the current page under it in the place where the breadcrumbs are? or just shift the main menu up a tad, and put the submenu/children under it (which would be good too if manipulating the breadcrumbs is too hard)

I am working on a website that needs the subpages to always be visible for accessibility issues. And this would be basically the perfect thing!