"Closing" for most people means gone, kaput, vamoose, no access, no books, no fun no more. What he's doing is dropping the open storefront hours while increasing his mail order and convention access. But I'm sure it still *feels* like "closing" to him, what with the incredible emphasis that any retail place has on when exactly the doors are unlocked and when they're not.
Yes, he's not going to be offering regular, frequent storefront hours. Considering the income/expense balance of his storefront hours, the real mystery is why he waited this long. (Note: not a mystery, it's very clear to even a casual observer why he waited this long.) But no, the main functions of the shop - getting great books to lots of people - isn't going away at all. In fact, it's quite likely to improve, along with Greg's mental health.