Pedal or hub meter?
Of the general population - hardly anyone. I think quite a few Cat 1/2 riders. That is mostly developed (300W+) IMO and in reach of many if they want it, but most do not.
Few even big guys holdi over 300W because an hour is a real long time. Big guys or fat guys can do huge short power, but if they did that for an hour, they would not be so big - see Froome, Wiggins, Schleck. I "believe" I held that in my 20s at 190-200# but was not measured. That opinion is based on speed and distance I road then. I did 400 miles a week pretty fast.
The poster known as Fudgy (we have not seen in a while) held >350W (I edited post and corrected spelling and power) for an hour up Palomar as did the cookie guy who rides clean. When VO2 testing my 15 year old I told them to set him for 350-400W FTP @ 130 lbs and they didn't, ignoring dad (these were Horner's guys). I knew junior was exceptional then and have huge regets they didn't run the test right. I got a refund, junior never repeated. But I believe he was around 350W / hour @ 15 130#. Guys like the AZ UAE pro later (not at 15) hold over 400W/hour (at 16/17). Latest USA pro ITT rider was so high (he is huge) that when they saw his power at 17 number were kept secret. If the numbers are secret they are better right? Numbers so high there were questions about equipment malfunction. He won the USA pro ITT at 21 (?) so that kinda settled that. My guess is he's north of 450 and you'd likely have to find Indurain or Magnas Backstad to see those numbers. I think he is a lean > 190#.
As Bike forums is open to search engines I avoid names. You can find these folks.
Last edited by Doge; 02-13-21 at 05:58 PM.