To SAM systems, not due to technical issues.
You probably missed this link:
http://www.rjlee.org/air/ds-aaloss/
USAF and USN subjected Iraqi military bases, power stations, and C&C infrastructure to a significant number of strikes (volley after volley of cruise missiles; F-117A Nighthawk paired with EA-6B Prowlers)
at earliest. These strikes were the first of their kind in history (surprise factor) and caused much chaos and destruction; many IqAF aircraft were total loss besides important infrastructure. No country had experienced this kind of technology and warfighting before.
When Iraqi pilots regrouped and somehow took to the skies, another surprise was awaiting them (BVR engagement capabilities of USAF and USN). Many Iraqi aircraft were blown to bits from afar before they could do anything significant - another FIRST in history of warfare.
Iraqi surface defenses were formidable enough to destroy a total of 75 Coalition aircraft throughout the course of the Persian Gulf War (1991) - impressive toll given the odds.
Iraqi armed forces where shaped according to Soviet philosophy and methods of warfare in large part; they were thinking on the lines of Vietnam War (understandably). They did not realize that Americans had completely evolved in conventional warfare methods since the days of Vietnam War.