They've been dealt a major blow by attrition alone. For those of us who go by demonstrable figures by the feds, and not inflated and ever-changing ones online, there were reportedly 30 members in 2001 - 15 years ago. Since 2000, there's been over 30 members or possible members that have died. Even if they weren't all members, and even if there have been new members made over that time period (which there's been no evidence of), it's obvious that the family's size has been drastically reduced (overly hierarchical and unrealistic forum charts notwithstanding). Couple that with the relatively few mob cases in Detroit, especially significant ones, over that time period and it should be fairly clear what the current state of the family is.

What's more likely? That there aren't many cases because this weakened and rapidly shrinking family just isn't a big priority for law enforcement? Or its some unique case where, to explain the lack of cases, people have to afford it an almost mystical ability to avoid prosecution (something no other family has done)?

It seems those who WANT to believe a certain narrative go with the second scenario, no matter how unlikely. It's why they'll probably still believe it years from now when little in the way of mob cases has continued to be the norm in Detroit.