25 years from now, we'll still eat similar things, use similar vehicles, transact in similar ways, but I think that the gap between the front of technology and those old things will widen. We won't see current cars quickly replaced, but I'm confident that Google & co will make decent progress with each year on their technology, then regulation, then adoption.
As for sharing your car, remember that eventually generations of future drivers will know little different. Or gradual cost pressure or advantages will influence decisions. It will start with use of vehicles in resort/campus-type situations, then eventually start to replace second vehicles then may be the only car for some people.
Driving age in Australia is 16. So there are another 9 years before someone is born who will reach driving age by the 25 year mark.
I know I would never want to share my car with strangers, any more than I would want to let strangers live in my house while I am at work. This may change I suppose, but if it does I think it will be more by force than by choice.