I assure you it's not. This thing is going to go into a 2U server, which is going to run ~$400 month for the rackspace, power and bandwidth. It's also not going to be purchased by folks building their own stuff from Newegg based on supermicro chassis and misc parts, it's going to be bought from Dell and HP as one part of the expense of a $30k+ server.

Could I build something cheaper and find cheap local colo to make it a 'significant' portion of TCO? Yes, doesn't change anything about the reality that this is not the target market so it makes no sense to be concerned about the cost in such a market. TBH if this segment of the market is your concern, you should buy a threadripper and hope the ECC ram you bought works with it. But, it's not the same market.