Yes, I'm making good money too. I've seen differently on streams though.
One of the bad mistakes you can make is to delete large areas to redo them, just to see your income suddenly go from +8000 to -14000. I saw a guy do it on a stream, he deleted a whole residential area to redo it, his income went negative, and because of less inhabitants a bunch of shops went broke, a bunch of industry had no workers, and within 15 minutes or so his finances spiraled totally out of control.
I've seen similar with traffic getting out of hand leading to abandonment, and someone investing all his money in a huge buildingspree, then discovering he ran out of power, and he had no loans or money to buy more power, and half his city starved.
I'm making a steady 9000 now, but if I look in my finances, that 9000 is only like 0.5% profit, so actually you're walking a fine line. However if you keep good reserves, and stay on top of things constantly you should be good. If it really feels too easy, the game comes with a default hard mode mod, which will raise upkeep for stuff etc to make it more challenging.