The problem is not necessarily with Siemens
Hackers certainly aren't to blame. Generally ranting here, but what I've seen make headlines is the 'hacker' (definintion in contention) equivalent of waking up one day and finding water all over your bathroom and realizing someone's been in there splashing water everywhere. Besides the overreaction to all it is, which is just annoying and expensive (time) is the overengineering to prevent it from happining again. Serious people seriously doing serious work seriously... we are the easiest marks. These kinds of 'hacks' and interested perpetrators are just as susceptable as the bathroom will always be to breaches using the same bag of tricks against the 'hacker.'
This is why marketing should merge with IT. Using well established PR techniques, and without having to waste time ever expensively fixing code that kind of already works; all that is necessary is to campaign against the personality, individual, group of individuals, activity or even thought of activity that actually utilizing that or any security holes is whatever we say it is. Besides distraction or diversion, another possible stacked method is to draw attention to a scapegoat, and the security researcher (or loosely put, 'hacker') could be used, as could any thing/one. To illustrate an example, if the view of doing anything unorthodox could be coaxed into sharing the reactions to other or all unorthodox activity, then anyone that finds a bug or any activity possible beyond that could share the same public condemnation of the pedophile, date-rapist or whathaveyou. Point being, from a business perspective, manipulating people is far less expensive than manipulating code. IT is all about work smarter not harder. If breaching code can cast a dubious new quality of 'insecure' on a system, then its valid to say that if breaching code were socially uncool enough, individuals wouldn't engage in it anymore. To prevent governments from doing it, the method we know that works involves leaking footage of them relentlessly spying on us, which explains all the water everywhere.