Enshittification and related problems can be a result of market forces just as much as they can be a result of monopoly/duopoly or a small cartel. Excess competition sometimes results in all firms scraping the barrel to squeeze out pennies, especially with technology (such as large online marketplaces) making pricing more transparent.
Marx actually predicted that ever-intensifying competition would destroy markets through overproduction, although he did not use the term involution.
The reason it doesn't work like that IRL is centralized marketplaces. If the winning strategy on Alibaba is low prices, bad quality and botted reviews to compensate then every seller has to do it to survive, because they can't get buyers outside the platform. That's not excess competition. It's a lack of competition just on a different level.
Well yes, that’s why I mentioned those specifically. But even if the marketplaces were split up, someone could create an aggregator to comparison shop and the same effects would apply. The problem for producers is that the Internet erases information asymmetry.
It’s also not just affecting low end goods, it’s a constant pressure on everyone, which is why many formerly upscale brands are seeing the same problems. It’s also a general problem with public companies, as large shareholders demand constant growth, as well as many private companies owned by PE where brands are stripped for short-term profits.
My experience is that the best low cost mid-tier products right now are coming from fronts like Vevor and Fanttik who do sourcing from noname factories in China. I’m not sure if their position is sustainable; it’s not like they have much of a moat. (I guess Fanttik has a team that adds some slick design to their otherwise utilitarian items.) If that model holds up then maybe that’s the future, but I suspect that they just have a temporary advantage thanks to a dual presence and connections in both the US and China.