I don't want a return to the old WP, but it's very painful to develop for the new WP because

1: The build steps for blocks are onerous, tedious, convoluted, ever changing.
2: The available Gutenberg features are liable to change in the middle of a site's development->delivery , so it's impossible to cost and more costly to support.

I'd never advocate going backwards, because the old system was lumpy and did need refactoring somehow.
My main problem is that when specifying a project now there's no certainty. What is the platform, and what are its capabilities? How do we even template now, do we do it with JSON, if so what are the final features? Most of the project still seems like its fluid as if in an Alpha / Beta state.

For example: Would you build using the new JSON based templating system for a Corporate site going live in September 2021? I suspect not.

I started a project recently using the new template system.
To add conditional to the home page required me to make a block with conditionals in (to call the relevant member content), and while there's a number of native make-a-block strategies there I'm sure we can all agree they are ALL more complex than something like " .

I headed down several blind alleys in an attempt to develop that site using only blocks, and JSON templates and patterns , but nothing usable was accomplished (the site requires things the framework doesn't yet support) and so all that work was set aside as unsuitable and unbillable. That's a bad feeling.
The templating system will be great, but it is in development, and while promising it still lacks key features, the tectonic plates are still shifting. It would be madness to build on that unstable footing.

I don't have a problem with WP becoming better, but the current WP version is in flux. It's very difficult to create and deliver sites in a shifting landscape.