There were 20 people working on this game when they started development. Total. I think they expanded to a little over 100. This isn't some huge game studio that has time to do optimization.
GTA5 had well over 1000 people on its team.
GTA5 had well over 1000 people on its team.
When making a game, once you have something playable, is to figure out how to package it. This is included in that effort. Determining which assets to compress, package, and ship. Sometimes this is done by the engine. Sometimes this is done by the art director.
When I did this. My small team took a whole sprint to make sure that assets were packed. That tilemaps were made. That audio files were present and we did an audit to make sure nothing extra was packaged on disk. Today, because of digital stores and just releasing zip files, no one cares what they ship and often you can see it if you investigate the files of any Unity or Unreal engine game. Just throw it all over the fence.