Well they also, like with Solasta, are using the SRD OGL. It's just the 3.5e SRD rather than 5e SRD. So they also, again like Solasta, are limited to only being able to use those things that are in the SRD and nothing more, which is rather minimal.
For some reason I thought 3.5e is more lenient in licensing (Pathfinder and all that) and it's 5e that has a more restrictive approach of only the SRD being OGL.
The devs can still add as much homebrew as they want, right? Solasta kind of does it. It's probably more a matter of limited scope/resources. Also tradeoffs - if they can put, say 6 races, they'll probably want those that people know from D&D so there's no complaining "why no X race". I'd love to see more games with interesting races, not just the bog-standard set of humans, elves, dwarves, halflings and maybe gnomes.
