They publish the schematics and everything else needed for you to do so. Not speaking for them, but I'm pretty sure they WANT companies to start from their design instead of doing their own thing and screwing it up because that just makes everyone look bad.
Examples of "innovative" designs that frustrate users and mess up everyone's reputation:
- That R/C circuit that releases the reset (EN) after power stabilizes
- Antenna design
- Changing the USB Mini-B connector to USB-C without reading the "new" (it's been 14 years...) specification and understanding that CC1/CC2 are wires that matter.
Still, someone will try to save a penny and make a board that won't boot reliably, won't connect to an A/P ten feet away, or won't power up when connected to a majority of USB-C power sources...none of those traits make the product look good
Development boards aren't really a product line of their own. They're meant for developers to prototype and validate a design around a chip or module. Companies do that, make their own boards, and then buy a bazillion chips or modules. The dev boards are just a bootstrap (sorry) to the process to get developers coding and learning about the parts.
Back in the old days, dev boards usually had sockets for analyzer probes, required NDAs to be able to even see, and were thousands or tens of thousands of dollars. They were very much an engineering-oriented product for hardware and software development.
That they happen to be usable by hobbyists for lunch money in modern times isn't an
unfortunate consequence.
I'm not Espressif. I've just been around the block. I've never known a chip company to consider dev boards to be a profit center on their own. They're a gateway product.