I really wonder what would happen under the EU or national laws here. Could be quite an interesting court case!
Turns out quite a few lawyers have apparently already considered this:
Vučković, Romana & Kanceljak, Ivana. (2019). DOES THE RIGHT TO USE DIGITAL CONTENT AFFECT OUR DIGITAL INHERITANCE?. EU and comparative law issues and challenges series (ECLIC). 3. 10.25234/eclic/9029. [
source]
EDIT: Interesting read so far. German Federal Court of Justice already had a case of bereaved parents suing Facebook to access their dead daughter's messages on the platform under German inheritance laws – the court sided with the parents, ordering Facebook to give them full access to the locked "memorial" profile and the sent messages. Though that's a different issue than inheriting a game store account, still the main argument of universal succession was upheld for a digital contract:
"The most important argument was that their daughter’s contract position is transferable according to principle of universal succession. BGH explained that the provisions of terms and conditions do not explicitly exclude inheritability"
Mind you, that was a very specific case where the daughter died in a suspect way and the parents wanted to find out whether it was a suicide or not – quite different case from Steam account inheritance, plus Germany obviously uses a variant of Civil law, so precedents don't really work the US way.
EDIT2: "
In other cases, for example in case of accounts created for purchase and music listening, there is no such justification for non‑transferability. Courts should declare such clauses unfair and accordingly null. Additionally, it can be argued that the principle of universal succession should in some cases prevail over the non-transferability clauses" and
"When it comes to the inheritability of digital data and digital content, since there are not any special rules in the inheritance law in Croatia applicable in this case, principle of universal succession also applies".
The authors argues that digital inheritance is basically already true under their existing laws in most cases and any licence terms against that automatically invalid*, but that a provision of digital inheritance should be put into later EU directives, as it would simplify it for the heirs, not having to resort to lengthy court procedures. The article was written before the Digital Goods Directive and DSA came into effect, so it might not be entirely up to date. Even if GDG and DSA would likely only strengthen that position of digital inheritability.
Interesting read indeed, even if IANAL!
*: Generally, under the EU law, most licence terms or ToS that contradict legal provisions or take away consumer rights are not only automatically null and voided, but even just
publishing such illegal ToS can get the company doing so a pretty hefty fine from the regulator.