Yes, that is true. I know when I switched publishers for one of my early books, I rewrote whole sections of it. Which ended up being way more work than I anticipated, because I could no longer get into the mindset I'd had when I'd written that book -- a major element of it was the conflict between doing what your parent/authority figure expects, and doing what you feel is best for you. No surprise, I'd written it in my 20s, when I was feeling my way through that conflict. But rewriting it in my 30s, there was no conflict to that, as I'd already resolved it in my own mind, so I had to invent another conflict that still worked with the majority of the book as written. It still feels stitched-together to me, and if I ever rereleased it, I'd probably take another stab at it before letting it out the door.