Maintenance and expansion are two different things. Governments of the day tend to favour big announcements for shiny new things, while simultaneously deferring maintenance whenever they can to redirect money to various other priorities.

I think you have to talk about how this is measured. Their network is huge, but frequencies are low and the maintenance costs per KM of track are very high relative to ridership. If you just think about the metric of KM of high-speed track, it's true, Spain has a larger network than, for example, Japan. But Japan is sending high-speed trains down some of its lines every 3 and a half minutes! Nothing remotely like that is happening in Spain.

I'm from Spain, I know it well. Just check what happened with short-distance trains.