Many New Cars Have No Spare Tires

I'll politely disagree. Spares are/were underneath pickup trucks, hangs off the back of wifeys RAV4. Then a Crovette and other sports cars would need 2 different size spares so space is a factor in some cases.
Recon which costs more?, a spare wheel and tire or the air pressure motor system? Mfgrs don't give a hoot about cost. The consumer covers the cost.
Yeah well most trucks and full size SUVs have plenty of room for spares, and they are normaly supplied with them or are readily available. So I don't exactly get your point.
By the way, TPMS was mandated by the Federal Govt. It wasn't the car manufacturer's idea.