You are incorrect about value. Pro sports teams have become the ultimate investment. They are scarce. There is no risk of losing your money: they’ll never go out of business, and the sale prices only go up. Plus only the elite investors can get in due to the amount of capital needed to buy one. The value of Attanasio’s team isn’t tied to fans in the seats it’s tied to what other teams sell for, and intangibles like “heritage” and “brand”.
Judging by the teams they fielded during his ownership, he is aware however the revenue generated from the smallest market in MLB is influenced almost entirely by the product on the field. Good teams on the field mean more luxury suite leases, more consumers of game broadcasts, more licensing fees, internet clicks, merch sales, ticket sales, concessions and parking, etc.
With their run the last 5 years the potential market revenue is very likely maxed or close to maxed out. So there really is no reason for him to sink more money in his team, and while fans might be disappointed to see Burnes and Adames leave for more money elsewhere the fact they do probably doesn’t bother him that much as an owner.