If I take your stance, taking it back to the 70’s/80’s where you had Haute Couture, Designer RTW, Confection (people who wears clothes by their local couturier/seamstress) and RTW by Benetton or whatever.
Everybody at that time uses quality fabrics. What makes the difference between designer RTW, Haute Couture and the rest is the artistic value.
Haute Couture and HF is only defined in that way if there’s an artistic value, courtesy of a Couturier/stylist/designer. The same way, we talk about Gastronomie as opposed to simple « cuisine », because it’s signed by someone who added an artistic value to something.
A sweatshirt by APC is probably similar to a sweatshirt by Celine in terms of quality and execution. So quality isn’t an interesting point of reference.
The same way, Jacquemus is HF despite not being luxury and despite being of below standard quality.
The word « luxury » has been used to define « fashion » since Bernard Arnault became the Grand Maitre of the industry.
Luxury goes with extreme quality, extreme exclusivity and no compromission on standards. But the term luxury can be applied to a car, a pen, socks, shoes or dresses.
The status originally came from exclusivity. Now it comes from the feeling of belonging to a club, through a name and what it represents.
What Hedi is doing is HF because it is signed. His name and his standards are the added value for it. The Artistic value of his work is in the project itself, not in the products. The project is Celine.