I don't think it's a technical difficulty but rather a management decision to allow spam as long as they have their adsense ads and it baffles me they just don't care about their end users at all.
I think being a monopoly with most competitors lagging a lap behind can make you this way, but with chatgpt catching up quick, Google better start thinking about their users now as it's a growing sentiment that their quality is totally bad nowadays and their uncaring attitude towards spam domains like Pinterest and spam search results where sites are creating hundreds of pages with same content and different heading is just not gonna cut it anymore.