Why? A dozen different reasons. Of course LLMs are one facet, there's also the commodification of software and infrastructure which means buying something off the shelf is far cheaper than running an engineering org in-house, there's also the fact that the market is extremely oversaturated with software engineers with hundreds of thousands laid off over the last few years, then there's the aggregate effect of advancements in PL and software system design which makes it a lot easier to do more with less, the broader homogenization of runtime systems with modern browsers and mature cross-platform toolkits... and many many other factors. All these trends are converging on downward pressure for demand, and I personally don't see any reason why the trend will reverse.