There's more options than just self-checkout and I would argue they work a lot better in FMCG, for instance the grab-and-go tech of AmazonGo, which has come way down in price and difficulty past few years.
The problem with something like AmazonGo is that people don't just like being tracked by CCTV. Making it more obvious will drive people away. To say nothing of people not trusting it to accurately ring up their purchases.