In the past, laminated glass was usually installed in the windshield, with side and rear windows being tempered only.
The difference is that tempered glass is per-stressed so that when it cracks, it shatters into many tiny and dull pieces. Laminated is the same thing, but with layers of plastic sandwiched with layers of tempered glass. Laminated glass will still shatter, but will be held together by the plastic layers.
In an emergency, small improvised, or purpose built tools meant to shatter tempered glass will be useless if the glass is laminated.
Most consumers have no need for a spare. The vast majority of drivers have cell phones and never drive anywhere more than 15 minutes from a tow truck or other driver’s assistance. Most people I know wouldn’t use the spare to fix a flat even if they had one.
It’s also not just about the cost of the tire. It takes up space, and decreases fuel efficiency over the entire life of the vehicle.
The hope of all emergency features is that you never use them. I’ve never been in a collision but I’m also not stripping out air bags to cut weight.
A spare tire is not exactly what I would consider a safety feature. It’s more of a convenience feature, and not even that in most circumstances.
In most situations it’s far safer to get roadside assistance. It’s not a great idea to be sitting at the side of the road outside the protection of your vehicle and involved in a reasonable that holds much of your attention. A professional with the right tools can change that tire in a fraction of the time, and they will have far more protection from the positioning of their vehicle and it’s lights.
In some cases, for some people, a spare tire could be a safety feature, some of the time. For instance, if you frequently drive back and forth across the US, there are lots of areas where assistance will be far away and potentially even unreachable. Nothing stops people from getting their own spare and throwing it in the trunk of it makes sense for them.
Why would I willingly give up my ability to help myself? Roadside assistance is great, but relying on it being available is foolhardy. If you only ever drive in the city you live and work in, sure I guess. I don’t trips of 40+ miles are that unusual though.
I’ve already explained why many or most people would willingly give up their ability to help themselves. Why you in particular might choose (or not) to do so isn’t relevant as to whether it’s something that should be designed into and sold with every vehicle on the road. If I have a flat then, depending on the situation, I’m likely to change it out. My mom? Not so much. In fact, most of the people I know would be scared to try it.
As I clearly said, you are free to buy your own spare. Most people rarely leave metropolitan areas and, when they do, they are usually on main arteries with lots of nearby infrastructure.
From a risk perspective, it’s a whole lot more dangerous to drive without a good first aid kit, blankets, and water. If anything, that’s what should come standard and be refreshed as regular maintenance.