Experiment report: I haven't used soap in the shower for a year
I use soap when washing my hands and feet, and shampoo once a month. I am a farmer/rancher so I am sweatier, dirtier and more cut up than your average person. I have repeatedly asked my wife and in laws if I smell throughout this time and I don't. My skin is no better or worse than before.
We have only had wide spread availability of hot water for ~200 years and have used soap for thousands of years, so I believe it's over use is just carried over habit from needing it when washing in cold water or less frequent washing.
A steamy shower and a homegrown luffa is sufficient (for most) because the physical scrubbing will remove excess dirt while the hot water melts excess oils for removal by the luffa. Using soap is likely to strip the natural oils from your skin and disrupt the natural microbiome on your skins surface, even if you're using a high quality animal fat based soap, you're just paying extra money to put back the oils that your body naturally produces.
I would encourage you to try this experiment for a week and see what happens. I welcome debate on this topic.

