Two new exotic RF L lenses coming in 2021?

A new rumor has popped up about two new Canon RF L lenses. While I think the focal lengths are certainly possible, I'm not sure the aperture and focal lengths would be that doable - or practical.

First up is an Canon RF 250mm F2.0L IS USM.

While this would replace the legendary L lenses on the EF side, I fail to see the reason for Canon changing the focal length. For a couple of reasons, it adds weight to bulk to the lens and makes it a less seamless transition for those pros already using one of the 200mm's already. Also increasing the focal, increases the theoretical element size from 100mm to 125mm, which isn't insignificant.

Next is an RF 500mm F2.8L IS USM.

Okay first, this would be .. well, freaking huge.

Here's the Sigma 200-500mm F2.8 and granted, it's a zoom, but the majority of the size and weight is to deal with the extremely fast aperture and 500mm... That's not a rebel on the end, that's a 1 series body. Now imagine that with your somewhat dainty R5.

So yeah, this one I just can't see unless Canon has come up with some physics-defying technology or anti-gravity plating.

The other lens mentioned is certainly probable and it's been mentioned quite a few times before, the RF 70-135mm F2.0. This lens makes alot of sense and won't be anywhere near the technical challenge of the first two mentioned lenses.

Take this rumor with a grain of salt but hope for the anti-gravity plating - I mean, that would be a game-changer.