Things you could do on a jailbroken PS3 or JTAG'd Xbox 360 (besides playing pirated games) != things you can do on an Xbox One with dev mode enabled, including but not limited to: running Linux; viewing and controlling thermal performance of the console; modding games/enabling cheats; theming the UI; playing game discs made for a different region (e.g. PAL); backup game save files (I think this is a given on today's consoles but it was more restrictive back in the day).

Of course it doesn't give you as much power as a jailbreak would, but it gives just enough power to make putting the effort into hacking the console not worth it.

I just don't think there was really anyone who was putting effort into hacking the Xbox One just because they wanted the feature that they now get out of the box- sideloading/running unsigned code in a VERY sandboxed environment that can't run retail versions of games.