Time is money to the buyer and value to the seller. It is the manifestation of great focus. Just as contracts make cash flow more predictable, dominant market share makes growth more predictable. So instead of a penalty for fall-off, the right buyer should be paying more because of an assurance of growth from their investment. Something the lawyers at the FTC do not seem to know is that consolidation spawns fragmentation.
Good people leave and often take good customers when the deal goes down.
If you are the best , you will own the customer. If you are the best , the acquirer will need your people, because they need to leverage the best within their organization. As part of the deal, make sure your people are rewarded for the pain of integration to minimize the risk of them leaving. The right buyer will penalize a seller for attrition. It's only fair.