I thought this was a well-known fact? Over the years its gone from "buy this thing from this seller" to "buy this thing and we'll send you one like it from eith

I thought this was a well-known fact? Over the years its gone from "buy this thing from this seller" to "buy this thing and we'll send you one like it from either the third-party bin or the Amazon bin depending on who your ordered it from", and finally to "buy this thing and we'll send you one like it from a single bin".