Jeah this is certainly true. Though we did use the 1DX II for quite a lot video productions. Especially on events its awesome
The 4k60 Image quality and AF on a gimbal works perfect and produced a lot of great footage
But for many people like advanced amateurs, freelancers in the "medium quality area" or students the budget is a a limiting factor.
The comparison is very difficult:
Sony a7 III with Tamron 28-70 -> about 2500€
-> Good Photo quality which will satisfy most clients, and also good 4k video quality on a nice fullframe sensor with a lot of features.
At Canons side you need the following, if you want to have the same or better performance:
Canon 5D IV, Canon 24-70 or something: 3900€ or something.
-> Resulting in a bit better Photo quality butno useable 4k video.
+ Canon C200 or Canon 1DX II: 6000€ (+ accessories and no IBIS, so maybe you need a gimbal).
----> So you end up with an investment of 10.000€ or more
Sony offers a performance which may lack a little bit here and there - but its not so much that any client would ever be unhappy with the photos or video you deliver in the end.
Sony may not have the BEST offer, but its MUCH more bang for the bucks and a way more versatile offer at a lower price point