In my experience, a spec is often public (or available for purchase by the public from a standards committee for a few hundred dollars, close enough in business terms), but the source code for your competitor's implementations is not available for any price. The first barrier to entry to become a competitor in many industries is to implement an 835 page (note that those are rookie numbers) spec, building software that is compatible with existing data formats or legal frameworks or network protocols or hardware or whatever.
This is another example of the many invisible silos that developers end up in:
1. Some are developing enterprise software for use by their own employer, the spec only exists because it's useful to help the dev team manage the project. In this case, it's totally reasonable to expect the spec to co-evolve with the code. If the release gets pushed out to Q3 or the target has to be adjusted due to unforseen implementation difficulties, so be it.
2. Some are developing contract software for their customers. The spec exists as a communication tool and requirements that allows the developers to know what to build and to inform the customer that what they've built has reached a certain phase of the billing process (including completion). You're on a clock, and if you're late or you don't do what you said you'd do then your customer isn't going to pay you.
3. Some are developing software for abstract customers - either B2B or B2C. Often, the specs here are regulatory or industry-standard, implementing the spec is the function of the business. You're releasing updates and new products to make year-end sales targets or snipe announcements by your competition, and advertising compatibility with various standards is a crucial bullet point in the sales presentation.
Bug reports, feature requests, and especially deadlines have different meanings in each context. The way AI development agents can be used in each silo also varies enormously!