Before we can (and want to) get tech workers to unionize, there needs to be a shift in culture in the tech industry. Right-wing libertarian ideals are very prevalent in tech, especially in Silicon Valley. This has been the case for years and has already greatly influenced tech legislation in the United States and the world. Class solidarity is almost non-existent at a lot of big tech firms.
That being said, there are of course many tech workers who understand the importance of the class struggle and who are ready to organize. I'll add some links to the tech workers coalition and to a podcast which unveils a lot of the hidden politics of the tech industry, tech won't save us.
On another note, interoperability naturally arises from well designed and largely adopted open standards.
He may just talk like that, but I think Doctorow is going through, as comprehensively as his allotted time slot will allow, the talking points he and the host have prepared beforehand. Keeping this in mind and taking into account the audience likely doesn't know what a "protocol" is, I think it's fine that he doesn't mention ActivityPub. Perhaps he mentions it in his book. I'll check it out if it lands in my local library's bookshelves.