It's always relied on a wealthy benefactor to subsidize it so that it can continue its reporting, and there's no particular reason why that should change now.
Perhaps such benefactors find other media properties more worthy of their subsidy?
Which would prove...?
Would prove that there's no such thing as an essential media brand name. I note that the general consensus here appears to be that as far as politics was concerned, TNR was already considered generally second tier and that it's main strength was cultural content. But as culture continues to fractionate into smaller and smaller pieces, the idea that an omnibus magazine could hope to adequately cover it has become more and more absurd.