one of the obstacles with other vegetables is their time to grow. Short term vegetables turn over quicker such as boston lettuce, baby bok choy, baby spinach et al, will show more profit then say potatoes, corn, certain squashes, Melons.
After the leafy vegetables and spices comes tomatoes, some baby squash, baby Cucumber, green onions, strawberries.
Those all can be grown in soilless mediums fairly well if you are dedicated in keeping the PH right and the food supply consistent. But larger tomatoes, green peppers, small baby potatoes are best grown in hybrid of soil, and flood systems. The soil can be reconstituted after every harvest.
Big time money can start rolling in for the professions with Aquaponic systems that include growing Tilapia. Used water from the hydroponic or flood table flows through the system filtered some what then dumped into a large tanks similar to what you would see at fish hatcheries, with the water eventually being feed back into the system.
There are indoor and outdoor systems. With indoor systems you have to factor huge electricity costs for lighting (LEDs are still not quite there yet and cost a fortune as compared to a 1000W light source). Outdoor systems come with their own problem such as heating or cooling, nosey bodies and drawing the interest of EPA who would like to know what you do with your runoff.
I did two years of dabbling and I only know surface details. It was productive privately, but costly and time consuming to maintain. My equipment was a hodgepodge of repurposed low cost item and like the article mentions, cleaning spray heads became a pain, and testing PH and nutrients by hand and adjusting was time consuming.
If I was a young man again I would specialize in that type of farming and get a postgraduate degree in that field. Round up some investors and then build and run a 4 acre outdoor system with filtering ponds for Tilapia. It’s estimated that you can gross slightly over 100k per acre per growing cycle. That’s why you want to do two cycles a year.
Or, you could use dirt...
The hydroponic set-up with tilapia is pretty neat and I expect we will see more of that in the future. Technology continues its march in just about every field of endeavor.