i dunno if this has changed but last i checked every item slot in minecraft's GUI was also rendering one of these 3D items except that they're rotated so they look like 2D images and as far as i know there's no caching going on
meanwhile block game just caches 2d images to use as an icon for every item in the game at startup because uhh, hello?? why wouldn't you do that???
before i started block game there were lots of things in minecraft that made me go "that's weird why wouldn't they do it this better way? i guess the microsoft funded multi billion dollar studio must have a good reason for it"
and now that i've been making block game i am starting to strongly suspect they do not, in fact, have a good reason for it
@eniko in that case I'd place it all at mojangs feet, still
unless my impression that all microsoft really does is copy everything to the bedrock remake (often producing logical mistakes/silly design differences) and staying hands off on java production is no longer true