I have done measurements at concerts. It isn't feasible/too embarrassing to measure continuously but at a Mahler concert of a piece I know well I measured the peaks, quiet bits and general orchestral playing.I have done some casual sound level measurements, on many genre of music, and found even 90db to be quite loud.
The highest peaks I've measure even on several classical pieces, were honestly somewhat unbearable to my sense of hearing at even around 100-105 db.
And yes the average level was in the 80s.
It was not due to equipment overload, but more my ears just get that feeling that is sounds "too loud".
The peak was ~125dB - I was in about the 5th row of the concert hall. The general level was 80-85dB.
I don't have commercial recordings with that much dynamics recorded, there probably are none. I do have uncompressed recordings I made myself at a music festival with a pair of microphones balanced by position rather than electronics.
They are the most realistic recordings I have. I do have some commercial recordings which are quite dynamic, but not the full monty.
IMO the reason a HiFi sounds too loud is more to do with speakers and maybe electronics being incapable that it actually being loud.
If I compare the same music on LS50, my big 3-way Goldmunds and my horns the 2-ways sound loud before they measure loud, the 3-ways are pretty good on everything but the loudest peaks and the horns, whilst being a bit more coloured than the big 3-ways, get the peak level without sounding too obviously "loud".
They are 109dB/watt though.
Generally a reasonably sized domestic HiFi is completely incapable of getting anywhere near orchestral concert levels without sounding "loud" IME.