I suspect this is one of those darned, it depends questions.
I have been slowly migrating from all different brands of components to the same brand for everything over the last fifty years. In a way, this is a reflection of the industry. A great system in the 80’s required choosing the best of class from different manufacturers. Each brand had a really great component made by the founder and a bunch of mediocre ones… think Pass.
Over time I migrated to all components from Audio Research. They offer top of class components voiced exactly the same in all categories… and putting all these together is shockingly synergistic. In this situation a full loom seems logical, and in fact, in general is really good. There is a known synergy between audio research equipment and transparent cabling. But I still had great trouble with my amp power cord. I tried many different solutions until I found the audio quest hurricane.
So I think, it is system dependent.