2017 Toyota Sienna wheels problems

Bought a 2017 sienna AWD on 7/15 from ventura toyota . Although the salesman there was confused whether it had a spare tire, my beef is with the manufacturer who doesn't show the lack of a spare in their sales brochure. They state that they have run flat tires and they have no room for a spare tire. The tires they provide on this new van are bridgestone turanza el400-02 . These tires are reported to have a tread mileage limit of about 15,000 miles and have no warranty on tread.

2017 sienna - 16886 miles. Firestone tires started wearing thin at 16,462 miles. Was told toyota does not handle that. Called firestone and was told to go to corporate store. Was told at firestone store tires were at 5/32 and nothing they could do because tires were not at 4/32. Concerned because family car, tires should not start to wear at less than 17,000 miles. At 16,886 miles while my wife was driving down the city road at 40 MPH, 2 firestone tires blew out.