People who need shove to be a full action are perfectly welcome to forgo their action on a turn when they shove.
Off topic, but since you brought it up...what? Forgoing your action is not at all equivalent to shove being an action by default
1.) Shove being an attack-equivalent action would mean characters with Extra Attack could shove multiple times per turn. This doesn't extend to the BA shove in BG3 though.
2.) BA shoving and willingly forgoing your action means you've lost your bonus action that'd you have had otherwise per RAW
Edit: To keep this post at least partially on topic, I'll echo what others have said. The (or at least my) Solasta Argument was that Solasta implemented 5e rules mostly RAW and was fun (according to me and the many positive reviews on steam). Thus, for many rules, Larian didn't *need* to significantly change 5e rules to make them work in a video game; Solasta showed otherwise.
