Regarding cost per unit; volume, volume, volume. How many can you make and sell within a fixed time period. Popular cameras from the 70's, even SLR's rolled off of simi automated production lines and were assembled from parts that were made on fully automated machines. a production run of 100K was not too much for a popular camera such as an OM-1 or K1000 or AE-1. This lowered man hours to produce a unit and cost per unit in parts.
Film will never, NEVER, reach that level again, probably not even 5% of that level. Of course back in the day SLR's were made by a handful of major camera companies. Nikon, Canon, Olympus, Minolta, Pentax, Konica dominated the mid to high end market, with Ricoh, Fujica, and Cosina subcontracting for Vivitar and many other house brands.
Now with a very narrow market only one or two or, at the most, three companies could support a worldwide market for new film cameras. Two companies if you have a high end brand, like Leica, then a mid to low end market company.
As to retail, well that's all inflated monopoly money, $500 just won't buy what it used to. So, it may be that even a 'simple' 35mm SLR could cost $300~$500 (depending on level of features) at retail. Us oldtimers can get along fine without a built in meter but a neophyte my balk, especially if he doesn't have one of us gray hairs there to walk him through the basics of exposure, DOF and motion blur control.
The foregoing is why, at this time, it just may not be possible to produce and sell a new 35mm SLR.
Low volume drives cost per unit higher.
High prices drives down demand.
Low demand lowers volume even more, again increasing cost per unit...
And or and on, until the company folds. (or in this case, does not even get started)
More thoughts on retail; Even a new Holga sells at B&H for $40! Add to that $2 for black tape, a necessary accessory. A almost all plastic camera, including the one element lens. So, it's no surprise a 'simple' 35mm SLR could be $400 new at retail.
