The first copies of any sophisticated technology are exceptionally expensive. The first Z80 microprocessor cost almost $2 billion (financed by Exxon). You can have one for about $4 today. It's a matter of amortizing the R&D across a huge volume of sales.
I use off the shelf parts to build computers that go on my research railcars. The CPU board is $800. The ADC board is $750. I'm working on a replacement for measuring the bearing temperatures using a PIC microcontroller. That allows me to measure 8 bearings with a $5 chip. I'm going to replace 16 channels of the 32 channel ADC with a pair of $5 chips. 6 other channels will be replaced with a different PIC. Another $5 chip. Two of the channels require very high bandwidth sampling. Those will be replaced with a stereo ADC designed for DAT recorders with a high speed serial link to a DSP capable microcontroller. The stereo ADC is $7. I'm still collecting parts and designing the final replacement. That is how you progress from an enormously expensive lab model with off the shelf parts to a custom implementation with parts specifically aimed at the objective.
Sorry, your explanation is much better. (Sheepish smile). I didn't bother to read all the posts, me bad.