They're general purpose from a technical perspective (although really only from a hardware perspective - the software not so much), but they're not sold or marketed as general purpose devices. People purchasing an Xbox are primarily doing so to play games.
They may have the ability to be general purpose platforms but they are specifically marketed as gaming devices for gamers meanwhile smartphones are marketed to the general populace. The Xbox and PlayStation sell maybe 10 million consoles a year meanwhile the iPhone is 200+ million.
they've been general purpose platforms for years.
they just don't look like it because the manufacturers are even more restrictive with access than apple.