That's because every new hip protein drink and organic chocolate brand that comes on the market wants its own webshop and app for branding, marketing, sales and payment which creates huge demand for web and app devs and the barrier to entry is relatively low, just buy a Macbook and sink a few months into following tutorials and building projects.

Not that many people need robotics experts and the industries that do, already buy from established players like Fanuc, Kuka, ABB, Siemens and the barrier of entry is very high, often a MSc being the lowest bar to clear with many workers in that industry having PhDs or postdocs so it's a lot of money and years of your life you have to dedicate before you can even enter and once you do the work may not be as exciting as one would expect, often times just updating simulink or labview models or days of just shoveling through ISO and regulatory specs.

I'm not saying there are no self taught robotics devs who earn well and play with cool stuff for a living but that's the exception in this industry, not the norm.

Yeah that's mostly on point. I have an MScA in mechanical engineering and my thesis was in robotics. I worked in industry (not robotics) for a few years but my current job is as an RA in academia.

I play with the the cool stuff all day, but pay is below industry average (for ME, don't even think about software engineer type pay).

This a great observation. Robotics requires a strong foundation in mathematics, control, embedded and similar, something that is unheard in typical software engineering roles. Plus, there is a "real-world effect" - if something works in simulation there is no guarantee it will work in the real-world (especially if the simulation is not properly designed). The software has to written in multiple programming languages, often minimum is C, C++ and Python. And everything stated here are software challenges, there are also mechanics, electronics and expensive equipment.

In summary, it requires more than a few tutorials to get started, it is multidisciplinary, and you have to deal with the unpredictable real-world.