The article says the units are 340 square foot.
According to http://www.building-cost.net a 340 SF free standing house, of modest quality, with heating and AC, in Fresno, should cost approximately 42k to build. Not counting land. I would assume that apartments, sharing walls and other structural elements, would cost much less per unit than the equivalent number of houses. Lets say 25k per unit in building costs
The apartments in question are built on .69 acres of land. A quick search of real estate shows that depending on location and zoning, one should be able to find equivalent property in Fresno for between 500k and 2 million. At the upper end, that would be about 30k per unit in land cost.
So, in theory, these units could have been built for 55k. 70k per unit if I am mistaken and building 69 apartment units costs just as much as building 69 free standing homes.
They spent 13 million. For 4 million, they could have bought a 71 unit apartment complex 4 miles away. 2 extra units, a mix of one and 2 bedrooms instead of what I assume are efficiency studios, and 9 million left over which could, using the math above, have been used to build at least 125 additional efficiency studios.
Double checking my conclusions, A quick search of the net shows me I could rent a small apartment in Fresno for about 700/month. Assuming that a small unit cost about 70k to build, it would take about 12 years to pay off if fully rented. If they cost 190k to build, it would take more like 30 years of full rental to get paid off, before a profit could be made. And they are still building new apartments in Fresno.