Not at all. This is one situation where you simply can't go back without destroying everything in that offending area, which is obviously under the building. it's not terrible, it's a light structure, and of course concrete is hard, so it's really not a big deal to make the structure "work". I just meant it's going to be unusually constrained to do so.
I like the suggestion of getting 4" blocks in there. That is clever. I might prefer to get a concrete stem wall in there somehow, lot of sledgehammering. Maybe the building has to be temporarily supported. Pouring that with the floor inplace would require you to leave a ledge outboard, but you can flash over it. That seems easiest to me.
Main thing is fix it and enjoy life. It's ugly but you'll prevail.