While I agree with the general sentiment, these are both standard sizes for Guinness and the 440ml 4 packs and 8 packs have been around for well over 20 years. Here in Canada, the 440ml are available in the multi packs while the 500ml are sold as individual cans. I’ve seen the same in the states. I think OP just saw the smaller volume can next to the slightly bigger one and jumped on the shrinkflation hate train without checking.
Yeah, this is not new and not shrinkflation… here in Canada the 440ml has been around for over 20 years in multi-packs, and the 500ml is available as individual cans.