Dashboard Summary on Memberships Page
This looks like a hardcoded limitation in CiviCRM, and changing that would require some development work (i.e., there's no workaround or trick to it, just needs code changes).

Interestingly, there's a comment in the code that indicates a desire to add support for ACLs instead of the sledgehammerish 'view all contacts' requirement: https://github.com/civicrm/civicrm-core/blob/master/CRM/Member/Page/DashBoard.php#L51

So my answer would be: yes, you're seeing it right; there's no way around this short of patching core, and it sounds like core is willing to be patched.