There’s only so much airspace. Without minimizing separation requirements—as was implemented with reduced vertical separation minimums, or RVSM, in certain airspace—there’s no way to squeeze more aircraft into a finite area. At the same time, there are only so many ATC facilities and controllers staffing them. Anyone who has flown down the U.S. East Coast lately probably has seen how the Jacksonville ARTCC is often saturated to the extent it forms an ATC bottleneck.
Meanwhile, more and more aircraft of all sizes and performance capabilities are plying the airways, many of them all wanting to arrive at LaGuardia at 1700 local. Increased frequency congestion is one outcome, as anyone trying to get VFR flight following near a major terminal on a good-weather Friday evening likely can attest. Some things have to give.
