Bethel isn't very concerned with the thousands that leave as long as they have a percentage or two of total increase
This has just triggered a theory so bear with me. In business this is known as churn - staff who leave (can also apply to customers) that are replaced by new ones.
When I worked at a specialist company a while ago a new manager came in. He wanted to secure his role in the long term by getting rid of any staff who might want his role. He caused staff churn despite this being expensive for the company (recruitment and training costs).
He made life so hard for all the people working for him they left when redundancy was offered. He then got new, willing recruits in who had less knowledge of the company and would accept him as an expert and not challenge him.
If the Borg has increasing churn which I suspect it has, then there are fewer experienced ones who can/will challenge the boys at the top. Anyone who has been recently recruited won't feel hard done by about changes in thought like the Generation. Anyone who does challenge them is removed, anyone who challenges elders on a local level is removed. It's all about keeping those with power in power.
Oh and as long as the money keeps rolling in...
MMXIV