For example:
Q2, I feel that blame should be given to both parties, and possibly even the driver, but all that depends on information that was not given.
The car company should test the stuff that it buys better, the company that made the cruise control should test their stuff better to avoid errors, and it should 'fail safe', in other words it should fail in a way that minimizes the risk of accidents.
Also, an error is pretty ambiguous, clearly it is one that seems to have a failure mode that is disastrous, but any driver should normally be able to disengage the cruise control if it would malfunction, so maybe the driver should carry some blame too.
Similar stuff applies to the other two examples.
For instance in #1 it might have been the producer of the cake (not neccesarily the supermarket), it might have been the delay between the purchase and the use, it might have been the person transporting the cake from the baker to the supermarket and so on.
In Q3 the error was made by the employee, but it may have been due to bad training, working too many hours or one of many other reasons that would change the take on the situation.
To assign 'blame' with this little information and so many unanswered questions is un-doable.
There is a reason why accident investigations take a while, all those questions need to be answered. And the reason is not to assign 'blame', even though in a litigious society that is how they are used, the reason is to make sure that we learn from these errors and change our procedures to make sure that it will not happen again.