Nothing is completely invulnerable to a modern integrated air defense system, but the F-22 and F-35 are specifically designed to have at least a chance to survive. They have low observability which makes them difficult to target, good sensors for avoiding SAM radars, and high power-to-weight ratios that give pretty good odds of evading missiles.

If those 5th-generation fighters are able to successfully suppress the air defenses then A-10s and other obsolete fighters can come in later for strike and air support missions. But against an intact IADS they would take extremely high casualties.

The survivability onion: https://i.redd.it/33lz51812ko31.jpg

Gun anti-air(AA) is basically useless against jets at this point (they fly too high and fast). For missiles, you can't really evade them if you're in their kill zone (they can accelerate way faster and turn way tighter than a human can survive). Your hope to survive a missile is to either not be "seen" in the first place (whether that's radar, or at somewhat less far distances IR), or to be far enough away that you can run away from the missile until it runs out of energy (aka don't be in it's kill zone and have enough speed/energy to flee. Speed is energy is life in air combat, turning hasn't really mattered since the 60s and dogfighting is a meme since turning kills your energy which makes you even more susceptible to missiles).

Ground based AA has big problems with actually seeing planes from far enough away at this point due to the horizon, and the ability of planes to shoot anti-radar and/or loitering munitions from over the horizon against ground based AA. Plane based AA is obviously better due to being higher so the horizon is pushed further out, and not having to be immobile (think cruise missile saturation attack against a ground based AA site), but if you have inferior planes or munitions (eg. Russia vs US/NATO), then investing more heavily into ground based AA makes sense as you'd never be able to reliably have air superiority to protect your ground troops if you relied on plane based AA.

Stealth (low observability is a better term) plays a huge role at essentially reducing a radar's effective range (iirc estimates I've seen are that the F-35's stealth reduces the S400's effective range from ~140km against regular jets to ~35km against an F-35).

This has all ignored the datalink/networking going on between all these different systems to eg. extend radar coverage, or how afaik SAMs are usually run in "passive mode" and are constantly relocating (https://en.wikipedia.org/wiki/Loitering_munition#Initial_rol... is a good primer on how planes vs ground based AA can actually be planes with "cheap" missiles hunting SAMs). Also, in a peer/near peer conflict A-10s wouldn't be used even after achieving air superiority and destroying all the SAM sites, because they're too vulnerable to even cheap manpads or gun AA and can only be flown in areas with 0 anti air threat (which is why the airforce wants to drop them and get Super Tucanos that can do the same job of dropping a laser guided bomb at ~1/10 the flight cost).

I cannot help, when looking at the peer-v-peer model, to be reminded of acoup.blog's excellent analysis of WWI stalemate. The concepts put forward of "knocking out the opponents SAM capability and achieving air dominance" might not work so well when the opponent is trying to do exactly the same thing. This is just a uneducated thought so please comment but it interests me.

Its unlikely either side will throw 100% of its air assets into the mix to achieve complete dominance, so there is always some planes / batteries around, and we end up with "we dominate that area, you dominate this". At that point, no-one has air dominance, and there is a "no mans land" over which some aircraft might be yours, or theirs, but you have to go through that part.

As soon as we have that situation, there will be discussions on "break out" - land forces getting through the contested area, but when you do, guess what, you have broken into the are where their air is dominant.

It seems you either have air dominance, or you fight in the air till you do have. But committing all air assets to do that risks losing them all, so stalemate seems inevitable...

Yeah, the problem is, IMHO, that modern AA capabilities are way cheaper then the air dominance hardware you to throw at the AA to break it. That's why stealth is so important, because you can get close. As is saturation with, e.g., drones. I always wondered how often the USAF would throw multi-billion dollar worth of hardware and multi-millions and multi-decades worth of training at a specific target. Especially over enemy air space, where you won't recover personnel or hardware. I always feared that if anything in a hot war between nuclear powers one side might be tempted, or forced, to resort to tactical nukes. Or powers decide to just not do it for financial reasons.

Joke was that Red Baron style wood and cloths bi-planes would be an alternative once the top notch hardware is expended. Easy to build, easy to maintain and pilot training is faster and cheaper as well.

Last time I talked with people heavily involved in future air combat, the scenarios were as follows:

Stealth vs. stealth -> most likely to end in a dog fight, fighters wont be able to engage each other at longer distances

Stealth vs. conventional -> most likely stealth gets a shot from BVR on the conventional aircraft, AVACS and the conventional fighter running under EMCOn change that, as soon as the stealth fighters fired the first shots, any surviving conventional fighters will engage again in dog fights

Conventional vs. conventional -> pretty much the same as above, only that both sides will get some shots before distances are closed

If anything, I understood dog fights will become again more prevalent due to stealth.