From a usability perspective, this is not necessary. The mega menu dropdown on all pages makes it extremely clear how to navigate to the relevant services we offer.
However, I am wondering whether a lack of a www.example.com/services/ page would confuse search engines, who otherwise will see www.example.com/services/exampleservice etc. for each of the service pages.
My thinking is they should be intelligent enough to know what's going on, but don't want to significantly harm our SEO if for some reason they really need to see a page for every URL slug element!
UPDATE: We do actually have a /services/ page, but it is not linked to anywhere and has no content on it. I suppose you need one if it has its own folder?