Comparing products’ prices at the supermarket is finally possible?

I'm (finally) back in Japan after 8 months back in my home country, and I just paid a visit to my local Life supermarket.
To my surprise, all the price tags came with an approximate price per 100g (or per slice or whatever other pertinent unit), which wasn't a thing before I left.

I'm used to this kind of price display and how easy it is to compare prices this way, so this is definitely a most welcome change!!

I'm curious if this is just something Life does now? Do other supermarkets also do it? Did a regulation come into place?
I went to Gyomu the other day and didn't notice this (but it could be that I didn't pay attention).

(P.S.: I did see it before, just only in some products and not all over the store)