The question should not exclusively be, "are video games hypertext?" Of course they're not, they're games. The similarities between the RPG format of game, and hypertext systems like the internet, are quite interesting though. The question that should be pondered in this situation is "how do video games and hypertext systems compare?"
The RPG, whether it is developed so that the user can only complete it in a certain sequence of events, or has full freedom to complete the game at whatever length they wish, has a very basic concept in common with hypertext systems. This is the ability for the user of either system to follow a path through either links in an HTML document as it is on the web, or by completing various parts of a story as it is with RPGs, or even other styles of games. Games like Zelda with side-quests are very good examples of this.
While functional, practical Hypertext can be seen as a tool to retrieve information, video game consoles such as the Nintendo Wii, have menu screens that are designed to do just that. The most obvious similarities between the format of most video games, and and hypertext systems can be seen with hypertext fiction. Essentially hypertext will make the document being viewed, interactive - which is exactly what Zork and other games from Infocom were designed to be, interactive fiction.
If viewed as a medium to convey information, then hypertext and video games can be seen as two different possible media, that have similarities and their obvious differences. If one used a very loose definition for hypertext, it may include many if not all video games that have some sort of intelligent user interaction. User interaction like this would basically consist of anything where the user has to make a decision to somehow follow a path. A game like pong, is not a good example of something like this, but for instance the Satellaview is.
Basically, the video game is a medium, that can be used for creative story telling, or other purposes, much like hypertext can be. Even individuals can write their own stories and convey ideas with video games. Hypertext is a different system, but their basic infrastructures have been very similar, and have definitely crossed over in the past, and will continue to cross over in the future.