Each stage just brings in additional psychosocial baggage and layers of alienation. It's totally dialectics- Baudrillard was one of those Marxian academics who got caught up in postmodernism when it was cool. You're just drawing clear lines around where those dialectical relationships change into new qualitative states, the same as making distinctions between the level of complexity in the village/town/city/metropolis.

Stage 1- Picture of a fresh loaf of bread at the village bakery. Yim-yum nutrients. It's an honest product that represents the self-sufficiency of your honest neighbours, the power of your community, and enough nutrients to live off of.

Stage 2- Picture of Wonderbread. You want the qualities of bread, you want the psychosocial connection of having the village baker, so the image looks like the first while it represents something entirely different. It's a less nutritious commodity being sold by a faceless multinational corporation. Each time you buy it, you undermine the village bakery and fill your stomach with a substitute that doesn't fully meet your needs.

Stage 3- Picture of ersatz bread. At this point the bread is qualitatively different, but it still pretends to be yim-yum nutrients even if it isn't legally bread and doesn't achieve any of the things bread does. Now the bread is a symbol of impoverished luxury- providing for your family, a quiet meal at a table, avoiding starvation- that actually solely exists for the industrial baker to extract maximum profits from the cheapest possible product. When you mentally accept the ersatz bread as bread and you eat it trying to achieve your bread goals, you betray yourself and become captured by the spectacle being presented. The more you starve, the more you trust in the power of the ersatz bread that the elites are kindly providing you to keep you from starving. At this stage there are so many different factors and influences behind the sign that it's the point where things become interesting for Marxists.

Stage 4- Picture of ersatz bread-flavoured corpsestarch. Materially we've reached a point of maximum destitution. Everyone still alive needs to eat and there is no food. There is no sawdust to mix into non-existent flour. The only thing the state can do is grind up the dead to process into nutrient paste, and they're selling it to a completely alienated population that has never eaten bread or even wonderbread. Their cultural memory of bread is tied to the spectacle of ersatz bread, itself a reflection of how miserable those people are so it's alienation-flavoured alienation. As they try to eat the ghost of the ghost of the ghost of food, it doesn't represent anything other than their own oppression. The Stage 4 image is so far removed from the Stage 1 qualities that it's purely a reference to other references with no original.