You can build a seat to survive 100G but how many g's can a human survive
Indycar drivers routinely survive and walk away from 100+g spike load impacts.
Two of the big reasons are nominal cost. About $300 worth of materials in bead foam seats (which cost appx $3000 to $8000 on a one of custom basis), and appx $ 50 worth of materials in the HANS Device (head and neck restraint system) - which sells for less than $1,000.
My point is not necessary to directly correlate Indycar and flight safety improvements, but rather that effective solutions are possible and are not always wildly expensive.