Is there any technical reason I am missing for which e doesn't have static fields/methods?
I've looked up the LRM and there is no mention of anything like this. There are workaround (like this one: http://www.specman-verification.com/index.php?entry=entry060612-105347), but I don't find it a particularly clean approach as it's not nicely encapsulated.
Good question. There should be no such technical reasons to not have it, and it might be a good idea to add static members to e structs. Its semantics would just need to be carefully considered, because of the aspect-oriented features of e, which are irrelevant to some other languages that have static members (for example, one question that would need to be answered is whether static methods can be extended, e.g., with is also or not).
However, it doesn't seem very critical to me, because a static field is, effectively, no more than a global field (or method, or any other kind of struct member) that belongs to a given struct's namespace. So, even without having static members, an easy workaround is to add such a member to global (or to sys), and make sure that its name has a prefix that makes it clear to "belong" to a given struct.
There is an important point, though, which does make static members more than just a member of global. In e, like in C++, there are template types. A static member of a template would be something that, on the one hand, is shared by all instance objects of a given template instance type, but on the other hand, would exist separately for each template instance (each one of which being a separate struct).
Not sure if the port-based workaround suggested at the above link is any better. I see it as an overkill.