Writers don't write for the money, although it's a nice side reward. Writers write because they love it.
If self-publishing was that easy to make money then everybody would do it. Compared to the sheer number of books being self-published each year, the number that makes it is very small. In my book, you have as much chance to make it self-publishing as you have being trade-published.
The choice really is down to how you prefer to work. Personally, I don't have the time needed to dedicate to the marketing, platform-building and other things involved in successfully self-publishing, I'd rather be writing anyway.
I'm still at the beginning of my trade-published journey but so far I wouldn't have been able to achieve where I am now without an agent. That's just my individual experience.