Status definitely keeps me flying with Air NZ. And while credit cards get you half way to gold, you still need to earn 900 SP to hit Elite. And so while yes, that extra 500 SP you get with cards is nice... To call 900 SP "easy" to me is ludicrous. Its still very, very hard and usually only achieved by those flying in premium long haul cabins. Its difficult for me to imagine that credit cards have exploded Elite numbers that much. Gold? Yes. Elite? No.
Rather than take aim at the FF program, the source of the crowded lounges is surely more likely things like the Koru program which has a *much* lower barrier to entry.
Although I am still almost never the victim of this crowded lounge issue. It seems to be mostly an Auckland issue. In my recent two months of flying around the country to many places but none of them being Auckland, I never had any crowded lounges. There were plenty of seats available.