The 169 ops per day comes from the airport reporting 61,780 operations a year, or just under 32,000 flights because landings and takeoffs are counted separately. Take out the military and air taxi, which are somewhat more known quantities, and you get about 60,000 operations -- 30,000 flights -- a year. That number is reported by the airport, and and yes, there is a motivation for the airport to over-report numbers. But it's not like the airport reports a number and that's just good to go. There is a little bit of analysis that goes into validating those numbers. The estimate is compared to air traffic numbers reported in the system, fuel flowage, etc. FAA uses those numbers to create a Terminal Area Forecast (not at all the same thing as what a pilot thinks of as a TAF), which is what funding justification is based on. For FCI, the TAF is flat through the 30-year planning horizon. So FAA is not expecting any increase in traffic through 2045.
As for the expansion to add 500 to 1000 feet, there may be some justification for it that is not readily apparent. I know of one runway extension in the works because an aerial tanker based there currently takes off almost empty and goes to a different airport to fill up. The other issue is that many large urban airports that have capacity constraints are in the process of trying to price GA out and push them to smaller regional airports.
By no means am I saying the operations numbers for GA airports are reliable -- they are not. But at the same time, they are not simple fantasy either.