I may be one of the very few members of the CR who has actually been a President of a OU member synagogue.
The OU is very hesitant to eliminate member synagogues, particularly those who actually remit dues. A very high percentage of the synagogues shown as members do not remit the head tax to the organization,
The synagogue I was President of in New Haven approx 30 years ago had been a member congregation for many decades. From the early 1950s until the mid 1980s it had separate seating, but no mechitzah. The OU was happy to accept its annual dues payment and provide services, subscriptions, etc. In the mid 80-s the synagogue installed a mechitzah by request of some new congregants. As long as a synagogue professes to be orthodox, has a rabbi who was ordained at an orthodox institution, uses orthodox siddurim and machorzim, they will be accepted. No one checks to see whether there is a chain across the parking lot on Shabbos or Yuntif, or if the women cover their hair.
The OU’s strength is in the number of affiliated congregations and members they claim to represent. I know many synagogues that no longer function on a regular basis (some only exist in name and to run their cemeteries) that still appear on the OU memebrship rolls.
BTW>>>this also happens in the Cnservative and Reform movements,,,,nop one wants to admit falling numbers.