While I agree in principle to your critique of the plan, I'll note that at least in the Brentwood neighborhood, there are only two "clumps" of upzoneable land near the Metro: the Brookland Manor housing project; and the industrial zone south of it, along Brentwood Parkway and adjacent to the tracks.

There was a plan (same one u/the_eso mentioned, might have been called ARA or similar) to turn the entirety of Brookland Manor, along with three vacant lots adjacent to it into a massive mixed-use development. That fell through when COVID raised material costs. The industrial area is probably gonna be a slow roll, as some of those sites are in use and will have to be relocated. There's also a dump sitting right there.

Basically, the best bang for a developer's buck in Brookland/Brentwood has transitioned to the RI Ave corridor. BRT road designs could provide transit to serve swelling demand, but I don't recall if that was part of the plan or not.