To say change to truck (I assume you mean the Heavy Goods Vehicle, rather than the pickup variety) quality bearings is a vast simplification. Cars manufactures over the years have been striving to reduce the cost of producing cars, the weight (improving performance and efficiency) and reducing the maintenance requirements of their cars.
This means we have things like sealed ball joints which can't be lubricated, spark-plugs which are expected to last for 75,000 miles, gearboxes without sump bolts as the oil 'never' needs changing and sealed units which cannot be opened and/or put back together without specialized tooling.
Trucks on the other hand are expected to have a very regular maintenance schedule with lubrication points (or complex single point lubrication), the weight of the vehicle parts is smaller in comparison to the load meaning there is little incentive to reduce weight (and even counter productive in low traction situations). They also have a much higher millage expectation within their expected lifespan and so are designed accordingly.
Well, having driverless cars will make maintenance more feasible too. I mean, if your car needs servicing, you can go to work, then send your car off to the mechanic's while you're at work. If it's something minor (like an oil change, or fluid replacement), the car'll be back by the time you're done working.
This means we have things like sealed ball joints which can't be lubricated, spark-plugs which are expected to last for 75,000 miles, gearboxes without sump bolts as the oil 'never' needs changing and sealed units which cannot be opened and/or put back together without specialized tooling.
Trucks on the other hand are expected to have a very regular maintenance schedule with lubrication points (or complex single point lubrication), the weight of the vehicle parts is smaller in comparison to the load meaning there is little incentive to reduce weight (and even counter productive in low traction situations). They also have a much higher millage expectation within their expected lifespan and so are designed accordingly.