This SEO company skips subcategory links. Is that good for SEO?

I was looking at some SEO companies for inspiration and noticed something odd, and was wondering if you could tell me if those things are done for a reason.

I was looking at the website and when I hover over services in the menu it shows SEO services and Marketing services subcategories. These are not clickable links by themselves. Though when I click on one of the lower level pages, such as content writing under SEO services, i see that the link is "/services/content-writing" . This means there is a subpage called services. But when i go to " /services/" i get a 404 page is missing. I've noticed the same occuring for some other websites.

I would think that a missing services subcategory page would not be good for SEO or site statistics, but the fact that I saw this at a couple of SEO company sites makes me wonder if this is true.

Could someone shed some light on this for me?