Did your mother ever theach you to read the article before posting. The guy is a custom carpenter already and owns his own custom carpentry business. One would have to assume that he already has all the shop tools and the skill to make his own cabinets. I have friends who have done the same and have made better cabinets for a small fraction of the cost of the press board crap you find in those big box stores.
I have what most would consider a pretty good shop setup. I know what it costs to build oak or maple cabinetry, or tables and chairs. To save $1000 on what would have been $5000 means I have an extra $1000 for something else, but I ain't building cabinets at a small fraction of the price.
Just for reference sake, good cabinet grade plywood costs about $45 up to $90 for the really good stuff. 4 sides can be gotten out of one sheet. Now you have the face and door back bottom and top, and maybe a drawer. Plus hardware.
If you have friends who built their cabinets for a small fraction than what can be purchased at Lowes, then they used crap wood and hardware. Otherwise they're blowing smoke at you.