This is wrong. What happened is that the amount of anti-aircraft systems deployed prevents both sides from deploying a viable air force.
No chance any F-16 or Migs can defeat systems like the Patriot or the Russian S500, that converge to targets at Mach 10. The only systems of the US Air Force with any chance of surviving on this type of environment, would be the most sophisticated stealth systems, that would not be deployed for regular operations. The future belongs to drone swarms working in tandem under the control of an AI....Sadly....
The key assumption is that stealth would enable the USAF to operate at will within or close to air defence zones, but this has not been tested against a near peer foe.
Any ground-based air defences today are useless and are just a sitting duck against any modern air force. It's just that the Russia doesn't have one. I know it - i passed training as a radar unit commander for Russian radiotechnical troops. We've been trained to understand that our mission us futile and we will never see anything of value on our radars - best we can do is to try to keep them from being destroyed (by employing false emitters, strategically switching off emission when threatened, and frequently moving) and out personnel from getting killed - by explaining them that HARM's shrapnel is small and command trailers have light anti-shrapnel armour and attack comes on a very short notice, so under attack the enlisted will be a lot safer sitting on their assigned places rather than running away.
When you switch on emission, you don't get to see anything today because ECMs do a very good job. But everyone can see you.
That's been 25 years ago but the equipment we've been trained to operate (it was brand new back then), is still the mainstay of the Russian radar troops, such as Nebo-SV. Slightly modernised versions are entering service now but they won't do a radical difference (modernisations are mostly about using fewer components from ex-USSR countries, because they are either politically hostile or producers gone out of business, not about specs improvement, anyway). In those years, Western anti-radar equipment and tactics have vastly improved though, so if it was one-sided then, it's most certainly so now.
Seems like the Army and USAF are stuck between a rock and a fog layer. There's now another warlayer and the Key West Agreement doesn't cover it. Perhaps we need a US Drone Force, because the drones the USAF/USN are thinking about are $10M F-35 wingmen.