You are very correct. HELOCs, however, are not as big a factor as they used to be. They will become more popular though.
Wolf Richter shows some nice graphs in the article linked below. He states that mortgages in Q2 were $11.4T and HELOCs a mere $320B.
https://wolfstreet.com/2022/08/04/trip-back-to-reality-start...