I don't necessarily have a problem with plain attire. Some understated pattern or material quality can be enough for it to stand the test of time. I personally have a plain black Nike tee from years ago which has a waffle type texture to it and I will never get bored of it. I just find ON's designs such as the faded kits to be ones which will go out of fashion, then come back in at some point, then look outdated again. Maybe that is just my perception? . I would say their designs are garish - you can do bright colours in a classy way, even tie dye/faded designs.
I don't understand why Lotto apparel seems to be ignored by pretty much everyone (at least in the US). The quality is absolutely top notch (slightly better than Nike and Adidas in my opinion), and their designs are also great; interesting colors/patterns, without going over the top. Also, the FIT is spot on. Never overly baggy or inexplicably tight, their clothes accentuate athletic forms.
Their women's clothing in particular, has consistently featured better looks, fits and styles than any other brand.
For me Lululemon shirts look like h&m shirts or Artengo. That’s why I don’t think I could spend 80$ on it. For me at least ON looks premium for example Shetlon tank top from USO black/pink one.
The Lululemon men's stuff is honestly awful. It looks like it was designed for hipster dudes that want to wear "athleisure" stuff for their trip down to the local starbucks. It's ill-fitting and ugly for tennis, kind of like Rublo (and I like Rublev as a guy and a player, but his clothes are pretty awful).