It's a nice idea, but it doesn't match my experience.
I find that almost every new embedded project comes with yet another vendor architecture, vendor-specific toolchain, documentation that's wrong, totally different peripherals and drivers, weird limitations, undocumented pipeline glitches, and so on. Even the CPU architectures and instruction sets are often different, if it's a DSP, or an SoC with DSP coprocessors glued on.
Basically, new things have to be learned often in that domain, at least with the jobs that come my way. For a while I got a bit anxious on new projects because I couldn't understand how to make seemingly broken tools do things the client wanted. Things like getting signal data into a DSP simulator when all the (GUI only!) buttons didn't do anything at all for example; but eventually I learned that it takes about 2 weeks on every new project of restraining the urge to swear, and than all the undocumented stuff, tools working differently than documentation says, secret header files and options, libraries that no client of the vendor has ever used and are full of empty function bodies or just broken, but sold to my client as if they are actually in mainstream use, weird memory models etc. starts to make sense and I'll be productive. So I just expect that on any new architecture project now, and it works out ok. Just budget 2 weeks of swearing-restraint at the beginning.
On front end webdev, there is infamously a huge amount of churn too. E.g. every time a new Webpack comes out I have to spend quite a while figuring out how to rewrite the config files for the new version for best results. WASM differs from asm.js; grid and flexbox are a new way to achieve what we used to do with floats, and there's an interesting new browser API each week.
But React hasn't change much in half a decade, and continues to be one of the main front-end frameworks. You could have learned React 4 years ago, and keep on using the same skills today and continue to be well paid if you're good at it. That pay is, indeed, at least 50% more than the pay offerred for low-level embedded, even though React work is way, way easier.
But remember, you can negotiate... Just taking a software dev position as an individual is not the route to the best pay in embedded hw/sw projects. If you can instead sell product development, where the client wants something built for them, and you build it, complete with project management, architecture, technology selection, supply chain, and subcontracting or setting up a project-specific company, then the scarcity of relevant skills works in your favour and the pricing is quite different - better. Those projects are great if you can get them, and sometimes a lot of fun.