The spec is behind a lead capture form so direct links below:

It’s 900 pages long, I don’t have a good point of reference so I’ll ask. Is this a small or large reference doc compared to alternatives?

Or phrased another way. Will no name, cheap devices ever properly implement this spec?

They will because there is an open source reference implementation that they can use: https://github.com/project-chip/connectedhomeip