That's a bummer, but in context, 260 out of 1.6 million is only 0.01625%.
NHTSA specifically does state at http://www-odi.nhtsa.dot.gov/owners/RecallProcess and elsewhere " There is no established number of reports that must be filed before NHTSA investigates an issue".
But besides getting a safety defect repaired by the automaker (which would be a form of reporting to them), it would be a good idea to report legitimate safety defects to NHTSA anyway. The dismissiveness and discouraging folks from doing the latter I've seen on one specific forum that I've pointed out (e.g. car losing power/stalling is "not" a safety defect :roll: and when it happens, it's "random" and should NOT be reported to NHTSA) is not a good idea in the grand scheme of things and can cause a delay in a recall (if one is warranted) due to low reported numbers.