I don't want to beat a dead horse, since my TL;DR initial counterpoint post has all these answers. But I'll state it slightly more briefly, so it becomes crystal clear for the prosterity of this thread:
Preorder lists running 2 months, or 5 years - doesn't particularly mean anything special for potential success or size of a run. In fact, the longer a preorder collects names, that is a worse sign for demand, than better. Keep in mind, case in point with Playboy: Since the preorder was up for 3 years - that means it took 3 years to hit 100+ names. Three years. No so popular as one may think. But...so be it... finally 100+ people at least, raised their hands. That satisfied us enough to go forward with the run.
A machine's original production number being huge means almost nothing. If we went by that, we'd be out of business from unsold bloated production in no time. There is rarely correlation between production number and playfield popularity. You just can't count on it. Often, it's the opposite of what you'd expect.
For example, Centaur... 3700 made. Incredibly, due to undisputed popular demand, we've re-run that playfield (8) times across 15 years. Each run with 60-100 units. Every time we'd put up a preorder, it would fill to 100+ in a mere 1-2 months. Plus - at shipping time, nearly zero no-shows.
Playboy - 18250 made. Yet it took 3 years to break the '100+' threshold, of people raising their hand. About 2/3 of that sent in their preorder in the first 2 months after we opened the inbox. Then it took a dragging 34 months for the final 1/3 to trickle in, finally taking us up and over 100. Then we flagged it as a serious re-run contender, alongside the main runs of new releases we are always doing.
Years ago, this kinda worked for a long time. As of 5 years ago, this would be cashflow suicide. As explained in detail in my TL;DR post earlier in this thread.
Just so we're crystal clear, here is an example of the way it goes:
"Playboy finally reached 100+ people. Last count on the preorder list shows 106 people willing to buy"
"Great. Let's put it into production and start CNC cutting"
"How many should we make?"
"106 people... three years to reach that number... don't forget about ongoing 40% no-shows"
"We'll make 70"
"Sounds fair. OK, we'll go with 70"
"If things go down the way they usually do, we should have about a dozen left over"
Insert ANY playfield title into that conversation, and that's about how it goes.
The only exceptions (where it went "Outcome B" as I described earlier) has been on Xenon last year, and Playboy last month.
You simply *can't* "knock out an extra XX" and hope they will be bought. Hope isn't good enough. We go by real life evidence. We err on the side of 40% no-shows, because that has been the proven outcome, time and time again (like 95% of the time).
It's not always about stock either. (even though bloating stock ties up serious cashflow and moves so slowly) Time is also finite. If we're landing on 30-40 abandoned playfields at the end of each run... times ~10 main runs a year... that's 300 to 400 playfields we would have to sit on, store, protect... and all the equity tied into them. But the main thing people never think about -> -> -> 300 to 400 playfields *could have been* 3 or 4 other full runs of un-run titles ! Think about that for a moment.
Any abandoned extras, had we known about it up front, didn't even have to be made. Had they been avoided, across those 10 runs, we could have switched cutting the NEXT playfield in line, 30-40 playfields sooner on each run. Meaning across a year of ~10 titles, could become a year of serving 13 or 14 titles. Same number of playfields cut across 365 days. So keeping production lean, and trying to stick to predicted outcome numbers, means the hobby gets more playfields. Time isn't wasted on those 30-40 boards, times 10 runs. Maybe folks never thought of production this way, but we do.