Have you ever started a business before?

Yes, you technically no longer own it once sold, but there's a huge amount of blood, sweat and tears that goes into building something from nothing - not to mention a sense of loyalty to your staff - and you genuinely do want to see it go into good hands and become managed well.

I guess a somewhat leaky analogy would be like giving away a dog you raised to another family and finding out later that they're abusing it. Yes, it's no longer your dog, but you're still going to care deeply about its wellbeing.