I tend to agree with the skeptics.
I have been clocked in DH at 100km/hr or 64mph - this was in full DH gear, in a full tuck, at the fastest part of a closed course, and it was scary as hell. It was no doubt the fastest I have ever skied. I find it hard to believe all these people hit that speed on an open run ever...let alone regularly.
My other "data point" was in a SG which also had a speed trap...I went through that at 81km/hr or approximately 50mph again in full gear full tuck (speed suit etc) at the fastest part of the course - this was also extremely fast, and definitely faster then I would hit free skiing - although the pucker factor was much less. I would believe in certain circumstances this would be possible on an open run...but still very rare.
I think the fastest you would see on an open run would be 45mph...most ski at 30mph.
Just like steepness...so many people get on 45degrees and think it is 60......there is a huge difference.
Regularly, no. First few runs in the morning when nobody is there and it's all freshly groomed, you can definitely hit 50+ and still be turning, in control, and safe.
I'll also note that you were on a race course. Race courses have turns. You can definitely hit 70+ if you go find a huge, steep groomer with nobody on it and just straight line tuck all the way down to see how fast you can go.
I'll also note the basis of your argument is essentially, "I've been X fast and I don't believe there are people faster than that so I don't believe the technology." Different people have different skill sets and levels of comfort. Pro DH'ers are hitting over 100 now. There's always someone better than you or me and anecdotes about personal comfort levels don't stack up against science.