I’ll say that clothing is not hard. Let’s not talk about cheap for a second. There is enough accumulated knowledge that it should be possible to make long lasting high quality clothing at an enormous scale. The problem in this is the cost and profit margins. It is much more profitable for clothing brands to sell ephemeral stuff that you have to buy over and over again rather than something they sell to you once in a decade owing to the longevity. It is not a problem of scale why fast fashion and generally available clothing is terrible. It’s a problem of economic motives.

Talking about cheap vs. expensive, I would say that it was true about a decade ago that you could reliably expect expensive stuff from good brands to last long. But as time has gone by this has begun to be less and less true. Luxury brands are looking to expand their customer base and profits because that’s what their shareholders demand. As such, they are also adopting techniques from fast fashion to produce lower quality clothing at a cheaper price to boost their profit margin. So you could buy an expensive item these days and it would be a dice roll for it to turn out long lived.

There is also the option of niche brands producing good stuff. Like Darn Tough Socks making indestructible socks. But sometimes these brands end up being acquired by venture capital bros who then run them in the ground.

There are a ton of economic factors that churn out terrible products. Large scale manufacturing is not important IMO.