This possibility points out why the conclusion doesn’t follow. The chance a system fails does not have to increase just because the number of ways to fail increases. The overall chance of failure might go down, even if the number of ways to fail goes up.

The author believes a more complex system involving more ways of failure will involve more instances of air bag inflation. But this doesn’t mean the author thinks every failure involves air bag inflation. There can be some failures that don’t lead to inflated air bags.

This possibility doesn’t undermine the argument. There can be accidental inflation even when systems don’t fail. That doesn’t undermine the belief that a greater number of ways to fail implies a greater chance of accidental air bag inflation.

The author’s conclusion is not about whether we should implement the new control systems. So whether there are advantages or disadvantages to the new system have no bearing on whether the new system is more likely to lead to accidental air bag inflation.

This possibility doesn’t undermine the argument. Whether airbags prevent more injuries than they cause doesn’t affect whether there will be more accidental air bag inflation with the more complex system.