Really? you mean these things are going to be available at WalMart so that untrained people can use them?
I really cannot see this being adopted. how are you going to slip this thing past the cervix and pubic bone? The whole reason that you need this thing in the first place is that there is literally zero room there. Also, the inflation is going to cause an even larger object to have to move through the birth canal thus exacerbating the original problem.
How are you even going to know if you have it on completely? you really cannot see in that tight space.
What about fetal distress? I cannot imagine that this thing squishing their entire cranium would bode well for distress which leads to many potential complications.
Maybe most importantly is the fact that this device would likely prevent the infant from ingesting the very important birth canal bacteria which colonized as flora in the baby's gut. c-section births lack this as well and they are at much higher risks for many things because of it.
This is a poor replacement for vacuum extractions (suction cup method) IMO. Maybe in developing countries it could be helpful (MAYBE safer for untrained midwives), but I doubt even that, given it's own disadvantages.