First, sorry for super long reply.
Some skis are just fast. Allegedly it has a lot to do with that particular piece of ptex holding more wax. The only way to know though is to test on snow. I presume the top speed racers get first pick of these fast skis. Afaik, these skis are kept in rotation from year to year just changing top sheet. Assuming they meet a change in rules. Maybe
@Primoz can answer.
There's less and less of this "keeping old skis". On alpine days of "new topsheets" are pretty much over, while on xc they were never there, and people were (and still do) skiing with 5 years old models. You can actually see this on tv. On alpine, they keep skis until design changes, of course if skis are still perfect on bottom (not damaged ptex, enough edges), and even this it's more or less speed only.
What makes ski fast... all together. It's not single thing. Ptex is cut from big roll and some parts are better for cold snow, other for wet and warm snow. And two rolls of ptex are not same, so no option to have exactly same ptex on skis made from different roll. Then it's the way they do ski. It's all still handmade work. This means no exactly same amount of glue, no exactly same laying materials up, no exactly same position in press etc. etc. When you add all this, you see there's no option to reproduce fast pair of skis again.
As far as hierarchy goes, it's normally so that good racers (actually their servicemen) go to company first, picks few pairs out of full batch and test. They keep several pairs and bring rest back. Further down the row you are, less options has your serviceman to pick from. It can still be you are lucky and you get fast pair, but with some companies (Head in particular) you won't keep them, because as soon as Rainer see test results, your serviceman get visit which normally starts like "well you know that ski... I need it back for X racer". So you do all the work, all the waxing, preparation and running it, and then ski is gone. Not fair, but that's life nowadays.
But yes, the only wat to see if ski is fast is to test them on snow. There's no way to say for sure ski will be fast just looking or measuring it. So at least for speed skis, there's lot of testing and skiing it (I actually still do some of this stuff from time to time for friend and his racer, as running 20 new DH pairs take some time for single guy).
For SL and GS skis, it's not so much real testing but more skiing it on course. And if it feels good, and your times are faster then other skis, then ski fits you and is "fast". But that's inaccurate that it's kinda hard to tell ski is really good/fast.
I'll try to respond to more later, but there is a big difference between recognizing a boot problem and correcting a boot problem. It isn't as simple as Internet pontificators say because you are adapting a messy human structure to a rigid exoskeleton.
That's something that always impress me, even though I'm not sure "impress me" is right thing. For boots, I never did much more then fit (basically punch and grind) my own boots, but I'm still impressed with "fitters" who look at client in store, take out their "it has to be this way" tables, and they know how to set their boots. But ok it's also true for recreational skiers with 80 flex boots, probably also number or two too big, there's really not much fitting needed
Novice question here
In the day and age of 3D printers and imaging, why can’t they take a molding of a skiers lower leg/foot and design a boot around it with the stiffness/reinforcement exactly where it is needed?
I would say it's simply too expensive for companies to bother.
So, what is Olympic gold worth? Would a different boot on your contracted ski give you a better chance to win Gold? This is a question I would be asking myself.
Thing is exactly like you said. Ski companies hold athletes hostage. It's not you can't say I want just ski and no boots, but thing is, you will either never get such contract signed (they will just drop you), or you might get through with contract, but you will never get top pick at their skis. So it's not like athletes have much of choice... even if they don't like it.
What blows me away are the junior racers who buy, and buy all from one company. Regardless of racer pricing, you can work around it. It's often not the best program at all.
It's about the looks. If Hirscher has everything from Atomic, and Kristoffersen everything from Rossi, then little kid races needs to be same, and he/she has to have everything from one company. It doesn't go other way, even if I'm wondering exactly same as you do. But nowadays look is more important then what's fast