Maybe the internet is complete. Programming was not that big until the internet came along. Writers started writing for web sites, some of them even started learning to code. Huge hoards of people were needed to "build the internet" as we know it today. That process has IMHO been stabilizing for a while now. Every local restaurant has a web site of some sort - some even have an event calendar that is updated regularly. It's not just Google and Amazon, the electronic version of the entire world has been built out. Payment systems are in place - even hobbyists or crafters can take payments online. It took 30 years with countless dead ends and restarts in a number of areas, but we finally have a stable functioning internet with common development tools and practices. Maintenance of this thing is going to take fewer resources than building it took. It kinda makes sense that jobs are getting harder to find.
I've been working in product development and embedded software most of this time, and I don't see too much change.
The internet != all software jobs. I don't think the internet can be complete anymore than an economy can be complete, but sectors can be mature and/or commoditized. Software is definitely not mature, but AI makes people think it is commoditized (it's not).
It's probably more cyclic than systemic and related to the larger economic trends, federal monetary policy, and growing protectionism. But tech is outsized in the economy, so I'm not sure which one is the horse and which is the cart.
I've been working in product development and embedded software most of this time, and I don't see too much change.