Again, I do not agree with the fact that FF will always lose out in reach against cropped sensor. Simply put, what you see on a cropped sensor is a smaller section (or cropped section) of the sensor, creating a field of view as if you are using a longer lens. To get the same effect, you either use a larger MP full frame and cropped accordingly or if you want, use a longer lens to get the reach and framing.
As for market segments, cropped sensors (1.6x fov) was created to look at the larger consumer market when digital SLR first launched. The 1ds Mark 1 (1d mark 1 (1.3x fov at 4mp) was at 12mp while the 10d and 100d was at 6mp. There were other models back then but lets for simplicity sake, just ignore the older technology. The segment at that time was simpler - entry level (100d), semi-pro (10d) and professional segment (1ds Mk1 for size or 1d Mk1 for speed). Models evolved from there but still retained the 3 series xxxd, xxd, and xd series. But as technology improves and people are more willing to spurge on more expensive equipment such as hobbyists and people who aspire to be "pro" start spending more money on the top segment. Canon of course decides to make things more interesting for a higher fps market with the 7d and hopeful that there is a big enough market (which there is) to milk more from this group who wants higher fps but still not willing to go the 1d Mark 4 or the 1dx route.
So now, you can roughly have the following segments:
1.6x FOV
1) 600d, 650d, 700d will be mass consumers, entry levels, people starting out with dslr or anyone who thing dslr can take better pictures...
2) 60d, 70d will be the semi-pro market or entrly-levels feeling that they have master enough to upgrade themselves to a better camera (better built, and slightly better features such as better noise control, etc)
3) 7d - the high fps segment but for users who felt that spending on the 1dx is way too much
Fullframe
5d mark 3 - some considered this the pro segment while some considered the semi-pro segment. Here users want full frame and higher mp over other things. High fps is definitely not needed for this segment.
1dx - now this used to be 2 segments in the past - fast fps 1.3 fov versus high mp FF. Canon has yet to introduce anything above 22mp (but just a matter of time). The launch of the 1dx is a testing point to see how the professional market segment will evolve if full frame and high fps comes together into its flagship top of the end mode.
The whole idea of market segmentation is to ensure you cover all the market. Creating products differentiation for each segment so that buyers' needs are being addressed or perceived to be addressed. With that strategy, it makes it a bit more difficult for consumers to chose and hopefully they pick one so that they do not go over to the competition.
I just prefer to look at size of sensors (cropped versus full frame) as tool for marketing positioning as compared to being different roles. In reality, the game can be changed such that all dslr are full frames and the positioning would be on features just like the good old film days where 35mm is 35mm - just 1 format for slr.
do u care to explain the 2 different market segments?
from my point of view,there are too many different type of photographers having too many different needs.
unless u are shooting specific genre,otherwise FF and cropped sensor does play a different role.
FF will always lose out in reach against cropped sensor.