And have made money doing this.
The domains I have purchased have mainly been for others so I have a good idea of the "mentality" of a domain seller.
In addition by being an owner I get approached by plenty of people who want to buy a domain that I own. I have seen every single approach out there on the buy side multiple times.
As far as "not needing to sell" the only 2 times I ever failed to buy a domain (for a client) was a domain that google owned where I was not able to buy that domain for a client. I even tried to trade them domains that I owned that they might need. And I was talking to the "right" people at google (high up contact referred by a well known person at google.) They carefully considered and then decided they weren't interested and would keep the domain that I needed. I used this strategy because obviously I quickly recognized that money was not going to make the deal (google doesn't need the money) which is why I went the route of a trade and it actually almost worked (where "almost" means they considered making a trade and took some time to ponder and pass around the domains I offered for any projects in the pipeline.) The other time was a domain that was owned by a Fortune 500 non-profit that a chinese buyer wanted. I was the go between. The non-profit didn't want to sell (buyer was willing to pay $50,000 nothing to sneeze at and the domain was not that valuable and well worth it to sell at that price). They buyer came to me because they had bought another domains from me and thought I could help them get this name. I still feel I had an angle to get the domain from them but the client didn't want to pay more money to try that angle. (Bonus points to anyone who can figure out that angle it's not a legal angle by the way.)
No matter what this seller tries to feign my belief is there is a weak point that would make him sell for way way less than 10,000,000 which of course is absurd for this domain. There aren't many buyers for this domain at even a $500k value. He may say he does not need the money but more than likely he is what I call the "lottery ticket" mentality where he is hoping that some big fish comes along and buys the domain for millions. While that could happen and he could be proven correct I don't think that will happen based on my 17 years of experience doing this.
The other thing is he is trying to hard to justify why he won't sell the domain and isn't interested. Shakespear comes to mind. As someone who owns plenty of domains I know exactly how many inquiries someone gets when they own a "good" short domain. Guess what? You don't get that many inquiries to be annoyed when you own 1 or even 10 domains.
I could write a book on this obviously but the way to approach (a seller like this) is not to send an email but to dangle a formal offer in front of him with a deadline and see what he says then. Or I might get into a plane and fly out and try to casually meet him to determine what makes him tick or uncover some other info about him that will help me buy the domain (which could be 6 mos. later so the events aren't tied together).