this may just be a usa thing, given the fuel regulations... but for the last few years a lot of new cars don't come with spares... in fact it's about 1/3 of cars...instead it's an added on option like rubber floor mats. Of course very few cars are optioned without the spare... but it's not a given you'll have one anymore.
Some cares a missing a spare tire because carmakers are trying to squeeze more miles out of every gallon of fuel. Here's what you need to know about spare tires.
www.consumerreports.org