I think cyclists do spend money on clothing, you just have to look at the proliferation of high end brands. Rapha are no longer an outlier of expense, there are some way more expensive. However this is mainly the roady market which is fairly international and also fair weather focused. Northern European MTBers are probably too much of a niche for a lot of brands.
This still leaves the question why local brands aren’t tuned in to the needs of their local markets? Just to expensive to get Chinese factories to produce low run lines?