Economy of scale is without doubt an issue. I remember a US colleague chuckling when I told him how many of our latest "state of the art EW system" we were buying. IIRC his reply was along the lines of that's about how many systems we order for our LRP (limited rate production) to get us through OT&E! He added that at the end of OT&E they would have expected just about to have ironed out the kinks.
The sad thing is that was in the days when we had aircraft fleets of (in some cases significantly) more than 100 aircraft. I guess we're not quite as well off nowadays...............