How it works for the most part is that they do indeed accept students off of the waitlist in that order....but only after they find the right 'type' of student. The way schools operate with this is that there is practice of selecting the same 'type' of student off of the waitlist as the person who withdrew their acceptance. This practice takes priority over where you sit in the waitlist.
For example, let's say an OOS 3.82 GPA / 33 MCAT URM (AA female) that is a 1st generation college student and comes from a family income of <$30k combined withdraws her EVMS acceptance because the COA is high. What EVMS will do is go down the waitlist (going in order, from upper 1/3 to lower 1/3) until they find a student on the waitlist that matches the same stats (3.80 / 30-33 mcat, URM / AA female, 1st gen, etc). If this student is found in the middle 1/3 or the lower 1/3, then EVMS will pick that student over, let's say, a ORM male in the upper 1/3 with completely different stats, OOS/IS, generation lvl, etc
As you can see in the above example, the waitlisted applicant's position on the waitlist matters, but only after priority of other things is taken into account. Another example that clarifies this further would be if there were two identical students that match a withdrawn applicant's stats, but one lies in the mid 1/3 and the other in the lower 1/3. EVMS is obviously going to pick the mid 1/3 one that matches the 'type' of person over the lower 1/3 that also matches the 'type'. So you can clearly see position matters.
Hope this clarifies any confusion you or anyone else had. If someone else that knows more about the process can add more information or edit something incorrect I stated, please feel free to chime in and correct me.
TLDR; there is a point as position on the WL does matter, it just isn't as important as other selection criteria that take priority