@jimm7497115 – That's right, it never has. The Background is a special type of layer, although that doesn't excuse the fact that the menu command is named "Select > All Layers". I guess naming the command "All Layers Except the Background" would have been too wordy.
In addition to Bojan's suggestion. If some files have a Background layer and others don't, you'll either need to use conditional actions or possibly relative keyboard shortcuts to avoid errors.
Select/target front (top) visible layer = Option/Alt + .
Select/target next visible layer up = Option/Alt + ]
Select/target next visible layer down = Option/Alt + [
Select/target back (bottom) visible layer = Option/Alt + ,
You can add the Shift key to select all continuous visible layers between the bottom and top, such as:
Option/Alt + ,
Option/Alt + Shift + .
https://community.adobe.com/t5/photoshop-ecosystem-discussions/select-layer-above-or-beneath-current-layer-with-a-shortcut/m-p/14737983