When I went from CFLs to blurples to the HLG quantum board I went from grams to ounces. My grow space is 20" deep x 44"wide x 40" tall and I've had 6oz of plants in the cabinet at once (about three weeks apart). Light is food and the better your lighting the better your results.
Genetics is the other critical factor. One of my favorite plants to grow is a fairly small strain that's usually only good for an oz but I love everything about it so it's always in my drawer. I don't smoke a lot, so yield is less important to me than quality.
There are strains Critical XXL, Auto Ultimate, etc. that can be legit half pound strains in anybody's hands and pounders on the hands of top growers. Every year the Ruderalis gets diluted more and more and the DNA gets better and better. We may never see a lot of one Kilo autos, but yields have been consistently going up every year for the last decade.
Get great lights, get good genes, the rest is up to you.