Unfortunately a good number of people making money with drones do not have a Part 107. Ask a Realtor who does their aerial photos, it’s usually either themselves or “some guy”. Neither typically worry about getting the license.
No harm in trying though since it doesn’t cost much to register an LLC, pass the 107, and get a used Phantom 4 for $300-400.
I operate big drones in the USAF for a living so I haven’t really pursued the sUAS that much, wish you good luck though!
I have a DJI Inspire 2, a Phantom 3 Pro, a Mavic Pro Platinum, and a Spark. I have my license, and use the drones for filming of vessel drydocking evolutions, heavy lift transfers, structural inspections of ships/marine vessels, and inspections for facilities where human access for the areas is high risk or expensive. I started out with the Phantom 3 Pro, then moved on from there once I was comfortable with operating the drones in tight spaces. I was able to obtain certification from ABS to conduct structural inspections for vessel operators in lieu of performing human visual inspections. This alone has brought in a sizable amount of income.
For large tankers/barges, the tanks have to be inspected every 3 and 5 years for integrity/scantling wastage. These tanks can range between 20 vertical feet, to 60 vertical feet depending on the vessel. Smaller vessels will have the internal perimeter staged so the inspectors/surveyors can visual inspect the structure. Larger vessels will have the cargo tanks filled with water to an elevation of 6 feet from the top of the tank, then perform the inspections using a raft and literally paddling around the tank. This is very expensive because the water then has to be disposed of as it will have oily waste from the petroleum product.
Smaller vessels will average 12K per tank to be staged, with most of the vessels having 10 tanks (+$120K). Larger vessels can run around the same average as there is less labor. I charge $4K per tank to fly and video the perimeter of the tank, and the internal stiffening. It takes me about 3 hours per tank, so I can complete a vessel in 2 to 3 days. So, I can pull in as little as $40K for 3 days of work. I secure about 6 projects like this a year, as some operators are hung up on "old school" inspections, and stay away from technology improvements that make the task more cost effective.
If you are considering becoming a professional drone pilot/videographer, look into the maritime industry, especially oil and gas offshore. You will need longshoreman's insurance, etc, but your AR will cover the cost 10 fold.