You need a better bookkeeper. In realistic terms, if you were paid $100 an hour and purchased that $3,800 keyboard, 38 jobs wouldn't even come remotely close. The payments come out of your net profit - not your gross income. From each of those $100 jobs, you must deduct the cost of transportation, car insurance, liability insurance, repairs and maintenance on the car/van, meals if you eat out that day because of the job's time constraints, amortization and depreciation cost of your original gear, office operating expenses, advertising expenses, telephone expenses associated with the business, heating and air conditions costs associated with the home office, retirement plan, etc... So, out of that $100 you took in for that single job, if you really do things right, your net income is probably in the realm of about $35 on average.
There's a damned good reason I didn't upgrade from my PSR-3000 for more than a decade - it didn't make good, economical sense. The keyboard sounded great, I sounded great to my audiences, and I didn't need to suck a big chunk of money out of my bottom line, which all looks great until the day you fill out that Schedule C.

Then, reality sets in. You suddenly realize that because you changed arranger keyboards and other associated gear like you changed underwear, you blew your entire year's net profit out the window and don't have a damned thing to show for working your ass off for 365 days.
Now, if you just perform for a hobby, you would be better off going fishing and playing music during your spare time at home, thereby eliminating the expense of being in business for yourself. Fishing is more fun, especially when you have a great day on the water, than performing in front of an audience and not making any money. When I was a bit younger and a lot healthier, I always managed to find a few days to go fishing each month. Usually got in about a half dozen trips to the Chesapeake's lower reaches, and one offshore trip for tuna and marlin. I can still fish for the big guys from the decks of the sailboat, but it's a bit more difficult and cumbersome because of the rigging. If you get to this part of the world, I'll be more than happy to take you out on the sailboat to catch some striped bass and bluefish in the lower Chesapeake. However, in the sailboat, it takes me about 3 to 5 days to get to the best fishing area, which is 180 miles south of where I keep the boat.
Gary