The problem with that is that IRST is not a counter to link 16 or really anything in any way or form.
In the real world Radar is king over every other sensor, even for OPFOR. You care much less about your enemy knowing you are there than finding and killing them.
IRST’s in the real world are utter crap for BVR as a primary sensor. This may change in the future with processing power, but in general they always run into the problem of, if you make them sensitive enough to detect things BVR reliably, they also detect all the false returns that are out in the real world (sun glint off clouds, glint off of water, hotspots on the ground, flares, etc…). On the flipside if you desensitize them enough to mitigate that problem, then you have dropped your range so much that they are really only useful in a WVR engagement.
This goes in combination with the fact that RWR’s in flight sims are way way too good. In the real world they are warning receivers, not ELINT gathering devices (how they are used in DCS). The vast majority of the assumptions going into how they are modelled in DCS are just straight out wrong (sensitivity, what they can detect etc…).
This is before we get to how horrible BVR missiles are in DCS right now, which preclude most realistic tactical options off the bat.
In the real world in an air to air situation I would want to be at 20-30,000 feet with my radar on, looking for the badguys at all times, regardless of if I’m in a Flanker or an F-15.
Long story short, radars are undermodelled, IRST/RWR is drastically overmodelled. BVR missiles are severely undercapable.