terms and conditions.
Yes, but not your interpretation of the rules. The software is subject to other intellectual property laws other than, for example, books, music, or pictures. Games are programs. So you are actually buying a license and not the software itself, it doesn’t matter if this is Cardridge for Atari 2600 or Playstation / Xbox disc or downloaded from an online store. You have this license, but you are not entitled to acquire software for which you do not have a license, such as server software or access to a working server. Thus, it is up to the consumer to pay attention to this when purchasing, and it is wise to wait for good reviews in which matters such as online DRM, offline games, game servers, etc. are discussed.
Effectively, there was also an expiration date on the Atari 2600, because at some point the controllers were no longer sold and the console did not last forever. For many of these consoles nowadays you also have to jump through hoops to make them work on a modern LCD TV …
Is that nice? No, absolutely not, but the server shutdown after 15 years for Rainbow Six Vegas is of course not surprising, it has stayed open for much longer than the average game developer leaves it open.