Not quite sure I agree with this. Any PM worth their salt, in either seat, should be able to intervene and save an aircraft down to about...maybe 20' AGL in a CRJ. (I have 4K hours in the mighty Canadian Reset Jet, have sat on both sides of the trash bag, and flew with a lot of people brand-new to the airplane.)

In a -900 you'd usually start the flare just after the 30' radalt callout, start bringing the power back at 20-25' and then make darn sure you were at ldle by 10' or 5' at the latest. (It's actually pretty much the exact same technique as landing the Guppy, now that i think of it.) Flying with a new FO, especially on the first few legs they were doing as PF, you'd be absolutely very much awake as you passed the 50' call, just in case. I never had to take the controls from anyone.

Thing is, though, with most accidents there are usually multiple causes. It's entirely possible that, in addition to the apparent non-flare in the video, compounded by the last-second roll resulting in all the force being absorbed by the right main, there could have been a windshear that happened at 10-30', and there could have been a fatigue crack or some other mechanical issue with the right MLG. Without seeing the report and the FDR data, there's no way to know.