Holy shit that's crazy bro.

Foil-faced insulation, I think, is completely vapor impermeable. If so, then you have to be ultra careful where you use it. Last thing you want to do is trap moisture inside your walls and end up with 50 tons of moldy stinky concrete wall filler.

In my climate zone vapor barriers are not really needed, so I avoid using them.

In cold zones you want the vapor barrier towards the warm in winter side of the wall, so that the steam from your hot cocoa does not condense into water droplets inside your wall.

If condesation is a concern then use the Rockwool product -- I forget the name.

Gosh, fucking concrete in the walls. Unbelievable.

Man, if you're brave enough to get rid of that shit... I wonder if closed-cell spray foam would replace some of that stiffness you are afraid of losing. (That would also be a vapor barrier, though).

If the studs are in good shape then I think the concrete isn't really doing much. There's that gap at the top of the walls. There's nothing sitting on top of the concrete, so I don't think it's really holding up anything.

I guess I'm just getting stuck on the idea of having such terrible wall insulation for the sake of keeping such a bunch of garbage inside the walls where the insulation should be.