The entirety of air combat history is that the plane which is not seen kills the plane that is seen 4:1 or more, yet you doubt stealth's central importance?
Let's say the stealthier aircraft A can detect the less stealthy (but still LO) aircraft B at 40 km distance and supercruises at M1.6
Aircraft type B can detect type A at 60 km and supercruises at M1.6 as well.
Let's use 330 m/s as M1.0. That's roughly 1 km/s closing speed if they approach head-on.
This leaves a total of 20 seconds advantage to A.
Sounds nice, but what if A is approached by B from the side. LO from side is not all that great, and closing speed is still 0.5 km/s.
Thus A needs to use a chain of fighters as a tactical formation, and the flank planes of that chain need to be over frinedly territory to avoid flank vulnerabilities.
Now it's still a mere 20 second advantage if everything works perfect. maybe 5...10 seconds for real.
Let's add free-flying decoys. Let's add B sprinting away at M2.0 once targeted or guessing it's targeted. Let's assume the MRAAM has a pk of 0.05...0.5.
Keep in mind type A has but six MRAAMs.
Now you need a 2nd line/chain of type A fighters that can fill a gap caused by A type fighters being forced to turn and run or being out of missiles.
The ''front' may be 600 km wide. Suddenly you need like 20 type A fighters on station for one chain.
At two sorties per day (including readiness issues) and on average 1 hour on station per sortie (lots of supercruise, tankers cannot survive LRAAMs and can't be close etc).
Now you have a need for 480 type A fighters. Which you don't have, so you mix with slightly LO 2nd rate aircraft developed in the 80's and 90's. You don't have enough of those either, so you have to use 3rd rate fighters developed in the 70's and upgraded with 90's radars at best.
Now you have at best one chain of 1st and 2nd rate fighters backed up by a second chain of 3rd rate fighters.
First chain wastes its missiles on free flying decoys and disengages, 2nd chain gets overwhelmed by red 1st and 2nd rate fighters.
By end of the day you are down to one incomplete chain of 1st and 2nd rate fighters that suffer from exposed flanks.
By the third day you have to resort to pulsing tactics, with little to no 'forward' CAP for most of the night, if not for most of the time.
By the fourth day you are down to defensive CAP and interceptor tactics.
And that's all before we think about attacks on 1st and 2nd rate fighters on the ground or about "stealth" fighters entering IADS traps.
Somehow I grew a suspicion a long time ago that having good area air defences and PGM SRBMs matter a helluva lot more than having expensive "stealth" fighters.