chicken........ egg
No bike maker is going to order a fork UNTIL fox says it exists. Fox takes the first step in that one.
I guess the wheel thing is a little different. I can fully see fox/specialized thinking they need to make a 15mm axle fork because getting a 20mm hub costs 0.025c more. After watching this system just go through 12 different BB standards, 9 new hub standards, 11 new headset standards and completely inventing a new wheel size..........that's still a completely bullshit argument though wouldn't you say? If they can convince a dentist on wednesday to buy it for saturday, they'd make it.
They need to just go 22mm. Because going back to 20 would be admitting a mistake, which at this point, is the only reason I can think they've dug in so hard.
As someone who has been a product manager for an OEM customer base (not bikes), you propose new ideas and technologies with your OEMs, but you largely listen to what they want to drive the direction of your development, even if it doesn't always make sense. It is rare for anything to make it to market without a commitment to buy from your OEM. Sometimes the OEM product manager will do detailed market research, sometimes they just go with their guts. They will always play two or more suppliers against each other to get the lowest cost possible. Either way, their are usually a fair number of people who know what the best technical solution is, but it doesn't always come to fruition.