How anyone could argue that small format cameras can ever ultimately compete with large format cameras beats me. (BJL, are you reading this? ).
Ray, you are again misrepresenting my opinions, as if following a false dichotomy that either that larger formats are always substantially better and digital photography will eventually move up to larger formats as prices drop, or larger formats have no advantages whatsoever. So I will try to explain my position one more time.
On one hand, there are some advantages to larger formats in some situations, particularly in extremes of high spatial and tonal detail at low shutter speeds, typical of larger film format usage. On the other hand,
1) these advantages are greatly exaggerated when one ignores aperture size limits coming from the need for appropriate depth of field or the acceptable size and weight of lenses, or when one ignores or denies the ultimate optical limits on angular
resolution of a subject ("lines per picture height", roughly.) [By the way, the gigapxl site is a good source on the subject of angular resolution limits.]
2) as one moves up the the ladder of possible formats further and further above the formats that are satisfactory for the majority of photography and photographers, each successive doubling of image area gives a smaller increment in image quality advantages and a larger increment in disadvantages like weight, cost, and need for lower shutter speeds. Thus, beyond some point, each further step up the format size ladder will be suitable for a smaller fraction of photography and photographers. Note that this ladder now starts from a mainstream dominated by sensor formats 1/1.7" and smaller (under 10mm diagonal): the 4/3", EF-S and DX formats are way too big to ever dominate mainstream digital photography!
By the way, the gigapxl images seem in reality to be of about 100 to 200 MP resolution; stunning, but far less than they claim. This can be seen by "pixel peeping" the samples. It can be explained by the fact that the design goal is for each of numerous resolution limits to give 50% MTF at the lp/mm needed for "gigapixel resolution", so that the combination is at best "gigapixel" only at the far lower MTF level given by multiplying all these factors of 50% together, so well under 10%.