It's free if you only consider the cost of licensing the software to the end user.
It's not free if you consider that there is a value to the user's time spent dealing with the upgrade, dealing with consequences like drivers or programs that no longer work ( and in the case of OP), rolling back to the previous OS.
For me, "free" or not, this is the biggest cost: the daunting prospect of investing an unknowable number of hours of my time.
It's free if you only consider the cost of licensing the software to the end user.
It's not free if you consider that there is a value to the user's time spent dealing with the upgrade, dealing with consequences like drivers or programs that no longer work ( and in the case of OP), rolling back to the previous OS.
For me, "free" or not, this is the biggest cost: the daunting prospect of investing an unknowable number of hours of my time.