It's just coming from a lot of speculations.
There was
Project CARS announcing its list of supported wheels last summer, and saying that more were coming. Some people thought this would mean console support and/or a new wheel coming from Logitech. Finally, they added console support for some of Fanatec wheels.
There were Logitech fiscal results for years 2014 and 2015 showing the group was starting to get better (after dropping many of its activities including console peripherals by the end of 2013). Some people saw this as a sign they would reenter this business.
There was this GAF member meeting Gran Turismo's creator, and being told by Mighty Kaz himself
that GT7 would offer support for legacy Logitech wheels on PS4, and that a new official GT wheel would be coming. Some people read that as 'a new Logitech wheel is coming', because reasons (the latest official GT wheel is Thrustmaster's T500RS.)
Maybe I've missed a fact/rumor, but I think that's about it.
I think people just can't accept Logitech stopped producing peripherals they didn't make enough money with.
I'm still bitter they dropped their Squeezebox audio network players at the same time, though, so I can understand that.