My understanding is that it is not lifetime - it is at AC's discretion whether you continue to qualify but some probably have it de facto for life.

For example YVR4Ever 's CEO will likely continue to receive VIP status as long as he/she remains CEO and his company continues to favour AC. When the CEO exits the role, they will likely lose the VIP status but AC may decide to confer it on the replacement CEO. William Shatner probably has it for life because the risk of bad publicity from taking it away far outweighs the cost to AC of giving it to him.

Like any corporate gift, people appreciate it when first given to them but over time the perceived value declines until you take the gift away - at which point the person suddenly remembers how valuable they originally thought the gift was and how evil the company is for taking it away. That's likely why there are very few VIP's in the system..