I’m sure you are getting paid a premium for the power you generate. If you were getting paid the “avoided cost rate” (which is what it would cost the utility to generate the next incremental kWh), you wouldn’t find it anywhere near as economic.
Basically, when I sat down with my solar installer and showed him my notes on how much power I consume each month, average peak solar hour per month in my area, etc., he and I designed a system with the understanding that it produces more than I need most days from mid spring to mid fall, and not enough the rest of the year. I didn't overdo it with the expectation of selling excess to the power company to make up the costs.
There's a monthly fee you have to pay to participate in the power buyback program. That fee is a lot more than the little bit of money I'd get back (the power company buys back at about 20% the rate they sell it to you). Thus, I don't participate in it. Thus, I didn't err on the side of getting a solar system that's way more than I need. That's why I average it producing a hair over 50% of what I need (more than that in the non-winter months, less than that in the winter).
Plus there's another benefit to not putting power back onto the grid. If you do that you have to set up your system to automatically shut off when the grid goes down (like during a storm). My inverter doesn't do that. So when the grid goes down I still have power (assuming the batteries are charged, which if I planned ahead of time for a storm they are). If I have another big tornado that knocks the power out for a week but misses my house I'll have at least some power. I can reduce my luxury power consumption like not running the hot tub and have all of the power I need (since tornadoes here usually occur in the spring when the weather is great for solar).