I get what you're saying, but I think there's an easy solution: just ask people who've experienced both. That way you're not experiencing the classic but very real problem of people not knowing what they want until they've got it.
At my workplace, for instance, not once in the history of the company has anyone with an office ever given it up, under any circumstances, to move into a cubicle again. Likewise, someone with a cubicle next to a window has never, in my tenure at the company, moved to a cubicle not next to a window.
As for standing desks, I didn't realize that people actively eschewed them. My impression is just that they're impractical for a lot of people to actually obtain. If your workplace doesn't provide them and won't on request, your options get sort of limited. I have a coworker who made a makeshift standing desk but it's not very ideal. I imagine a ton of people are in this situation.
Ok, but let's suppose that, by some ingenious study, you're able to determine that nobody prefers the open office, everybody prefers private offices (quite strongly), and yet productivity for the company is better with an open office. That's pretty counter-intuitive, but the world is filled with counter-intuitive things. Does that mean that companies should all switch to open offices?
Should a company do something just because it can be shown to increase productivity? I don't think that's necessarily the case. For instance, it might be that the productivity gain is somewhat minimal and that over the years a number of great employees are lost (or not able to be hired) due to the office layout. So in that case the illusion of temporary increased productivity will lead to a long-term net decrease in productivity.