I'm finishing up a site for a client that uses Gutenberg heavily. It was difficult getting the theme together at first due to the constant changes to Gutenberg, not to mention the learning curve and architecture decisions that we had not encountered before while structuring the theme and files. (where to store blocks, how to logically split and store reusable template parts, etc)

In the end, it turned out really well, and the client couldn't be happier. I custom built 20+ components for them as highly-customizable Gutenberg blocks, plus a few flexible layout items - like sections and columns. They are now able to build amazing looking pages in under 10 minutes. Pages you could never do with the classic editor or would take extensive custom templates to handle.

The completed project feels cleaner from a file/code structure perspective and looks great on the front-end. I'm actually a little impressed with the flexibility I was able to bake in.

I agree WP development has grown more difficult by magnitudes. But the end result is also far superior to what you could achieve with classic editor + plugins.