I mean, I really would sell for $10MM. But I think I'd be giving someone a real steal for (much) less. Like, sure, I could use $100,000, but does that mean I should sell a more-valuable asset that I happen to own for that little? If so, why?

To answer that question, ask yourself if you would buy milk.com for $100 000. Probably not, I'd wager. The only reason to not sell is the hope that you might get more for it in the future.

I also wouldn't buy milk.com for $2000. Does that mean I should sell it for $2000?

In any case, there is also a time / hassle reason to not sell: It would mean the loss of the only personal email domain I've used since 1994, and that would make for a _lot_ of updating (and crossing of fingers hoping I didn't miss something important).