It seems that people who leave IFB end up eventually leaving church altogether. My brother, who was a big influence on me getting saved, left his IFB church for SBC then went to a non-denominational now is out of church completely.
Where I'm originally from there were no SBC or IFB churches but Regular Baptist churches (GARB). I now attend an IFB church in my new home state and my friend who I met in a GARB church in my old state started an IFB church the only one in a 40 mile radius.
People leaving SBC going back to IFB my guess is because of how they are letting Critical Race Theory to take hold and because of Beth Moore.