The HLG format, by design, has the lowest saturation of all formats because it preserves the chromaticity of the scene as imaged by the camera; all other formats increase saturation compared to the scene as imaged by the camera. Earlier studies have shown that colorimetrically accurate reproduction of natural scenes does not necessarily ensure the highest perceived image quality and a reliable enhancement of perceived image quality can be produced by selectively increasing saturation values.
ITU-R
During a presentation (May 18, 2021) on the future of live HDR production, broadcast industry expert Prinyar Boon explained his decision not to go with HLG for live football and rugby events (ca. 2019):
“We kind of quickly… actually, did not use HLG, because at the time, the – let’s call it the natural look of HLG – was not very commercially compelling. It wasn’t the ‘sports look’ that they had today, so we went with the choice of PQ.” – Prinyar Boon, Product Manager, SMPTE Fellow, PHABRIX
“It can be observed that BT.2020 generally provides the highest saturation while, by design, HLG provides the lowest saturation.” – ITU-R BT.2408-5
“The PQ signal can represent highly saturated, bright highlights that would not be reproduced by an HLG system. The HLG system does not present such colours because they cannot be reproduced in a perceptually consistently manner on all displays. If such colours are introduced, perhaps during the grading of a PQ signal on a bright display, then they cannot be reproduced on dimmer displays whilst still preserving creative intent. The use of such colours therefore leads to inconsistent reproduction of the picture on displays with varying brightness.” – BBC, Frequently Asked Questions on High Dynamic Range and Hybrid Log-Gamma
Header photo: ITU
The Daejeon Chronicles 
‘highly saturated colours are not commercially appealing.’ Quite the opposite of how TV manufactures demo/sell their TVs.
It was the lack of saturation that was considered to be not commercially compelling.