Sinking stem wall in garage

[Harvey Sandhu]

Hello everyone!

I bought a Duplex last year built in 1973 only issue I noticed at that time was cracks in garage floor I asked home inspector if it was a concern  they said its common for older houses to have cracks in the floor, but now a year later I wanted get the cracks fixed my contractor told me  there's bigger issue floor is cracking on 1 side because Stem wall sunk 1.5 inches. I went through my home inspection report again and they labeled those cracks as common cracks, now its gonna cost me around $8000 to lift stem wall. 

Does anyone know if this was something home inspector absolutely shouldn't have missed?

Any advise is appreciated. 

Thanks