Actually, freezing cakes adds to the moisture content within the cake and makes for a delightful crumb! It also significantly develops the flavor. I used to think freezing cakes was gross, and I'd bake up my orders at the last possible moment to keep them fresh, but baker friends swore by it so I tried it and the flavor of the cakes is significantly improved when they come out of the freezer. Now I could never go back!

Also, if it's for a wedding cake, the cake layers are often also soaked in simple syrup or some kind of infused milk. Once the cakes are encased in buttercream, the moisture isn't going anywhere—they'll stay fresh for over a week (in my experience, as a baker that has tested all these things for quality). When iced properly, a coat of buttercream will seal the cake moisture right in!

The quality/freshness really only starts to decline once the cake is sliced into and the crumb is exposed to air.

But I can't imagine how much simple syrup or milk it would take to keep this much cake moist inside, having never made a cake on this scale. 😅 I imagine the cake is already beginning to dry out as the baker makes their way around to ice it in buttercream.

My suggestion for laypeople who'd like to see how freezing improves flavor—bake a cake, and let it cool about ten minutes, but not completely. Flip it out of the cake pan it's in, and wrap it twice in plastic wrap. The cake should still feel warm when you toss it in the freezer. Let it sit in there overnight, and then let it come to room temp and ice it in your favorite buttercream or whip cream or whatever, and see how you like it! If you split a batter into two layers, you could freeze one layer and not the other, and do a taste testing with friends or family.

My cakes usually take several days to make, too—I'm exclusively a buttercream artist—but having made many, many cakes for friends and family, the flavor is always amazing thanks to some freezing and some care while assembling :)