I run Renthal 780mm wide bars on my FS and 740mm on my XC HT, when I get back on the HT the 740s feel very narrow for the first few minutes.
I ride on mixed trails around Winchester and there’s only one gap I just can’t get through with the wide bars on, singletrack through the trees is fine provided you’re happy to dip the bars to the side to get through narrow gaps 🙂
Back in the day, on 570mm bars with bar ends, there was a gap in our local woods that you could only just squeeze through. I bet it’s impassable nowadays 🙂