Also, maybe they reasoned the transporter didn't take long to get going, so there wasn't any reason to keep it "idling"?I do miss some of the sound effects from TOS that even regular weekly TOS dialed down on or abandoned. The transporter platform "throbbing" from "The Cage" is one of them. But I can understand why that effect would have added money to the weekly postproduction budget and distracted from dialogue in the transporter room.
But you're probably correct: budget constraints.