Kardalis' post is a good post. EULAs are not private law. For the same reason as you can't sell yourself into slavery, companies can't put anything they want into a EULA: The law legally limits the kind of contracts its subjects can enter into. Or, rather, the kinds of contracts that are enforcable.
In Germany, specifically, Paragraphs 305-310 BGB regulate AGBs (general terms and conditions, which End User License Agreements fall under). I can see at least 3 points under which the forfeiture of the right to class action lawsuits is illegal, and it's explicitely stated that a EULA can't contain a clause giving one party the right to unilaterally decline service without a good reason. That means that even if a judge were to rule that valve is offering a service, rather than selling a license, they agreed to provide this servicee without a clear temporal limitation, and unless they have a reasonable cause, they can't terminate at their own discretion.
So yeah, steam's EULA is illegal as fuck in Germany. And it's not just one part; depending on the judgement, the inclusion of a single illegal clause can make the entire EULA invalid. And what's more, under German Business law, the use of illegal EULAs can give competitors a claim against the company upholding the EULA in question, if they can prove that they were at a competitive disadvantage due to the transgression.
And yeah, the german consumer protection agencies definitely have the resources to take on Valve.
So, being german, I don't worry. If valve tries to enforce the latest EULA, or cuts off service, they're just begging to get taken to court.
And since I'm studying law, that just means more work for me. : P