Check out how useful the 80% discount is on DualGap: https://replay.faforever.com/18287108. I produce a lot of bricks while constantly overflowing and donating everything to eco (and you are supposed to to win late-game on DualGap). So, basically, when a factory discount goes a bit beyond 20% (T3 fab gives 20%, T3 mex gives 12.5%), I don't stop production, as it becomes mass generation and I can reclaim if needed. In the end, I have around 15 factories producing bricks.
I also build T3 pgens far away, because you only need factories, fabs and shields there (maybe UEF SACUs with 50k projected shields could help save space instead of structure shields).
So, it feels like this strategy work best on bigger maps, as it takes time to build the infrastructure and on smaller maps, you need to somehow survive early experimentals.
P. S. Bricks aren't total crap underwater due to their HP, discount, and immunity to battleship ground-fire.