The reason the US kinda sucks on defensive missiles is that their docterine states offence is the best form of defence and they have built their Air Force to "ensure" control of the skies. The believe they can neutralize any air defence through ECM, Stealth and by attacking radars and launchers. It is a connundum. If the US was to fire a wave of cruise missiles can AS 400 take them ALL out? How long can they keep up this defence? Once you have a hole in the defence you can go in and finish it. It depends how sophisticated the spoofing, decoys and counter jamming is. Hopefully we never find out who is right.
The Russians are not asleep, they have carefully studied the way NATO and the US operate, the main point being Russia is not a third world country with one big Fixed SAM defending their command and control centres and communications hubs that can fire at one cruise missile at a time, with an airforce with little command and control beyond that controlled by those command and control centres.
Fire 4-6 cruise missiles and the SAM sites are overwhelmed and the major radars and Comms centres destroyed the defence of that state becomes independent individual systems that are really weak on their own and can be destroyed one at a time fairly easily with a well organised and trained and armed force like NATO or the US.
Their problem is that a Russian system like a single S-400 battery doesn't exist... there are dozens of radar sites in every area with different sized radars and SAMs and other systems all interlinked, and those detection systems reach to well outside Russian territory.
Any US attack to take down an S-400 will be very risky because any major cruise missile attack requires cruise missile carriers which are themselves vulnerable to counter attack... B-1Bs, Subs, Ships, tactical fighters... once they start launching missiles at a Russian S-400 system they become fair game and I can promise you that to launch the large numbers of missiles needed to overwhelm an S-400 battery you should expect to lose a lot of launch platforms and still not expect to get that S-400 system because it can defend itself and if it runs out of missiles it can move while TOR and Pantsir batteries continue to shoot down cruise missiles in enormous numbers... and of course local PVO aircraft monitor incoming threats and deal with some as well...
With a fully operational Russian network even Igla-S and Verba MANPAD batteries can effectively shoot down cruise missiles... the Barnaul command system can easily detect and track such weapons and cue soldiers to point and launch their missiles at the best times and places to bring down such weapons.
Ongoing improvements like Pine and S-350 and S-500 are only making the problem worse for the US.
Russia builds systems like AS400 because they have a massive country with huge empty spaces and long borders to defend. The US has airbases all over their counrty .Their defensive requirements are very different.
No. What is different is the method of providing air defence, and it is more to do with political power and stepping on shoes... the USAF has claimed all responsibility for keeping the skies over US military operations exclusively for US forces and their allies... and with their current focus on F-35s and F-22s and stealth it seems they are dropping the ball.
The Russian/Soviet air defences have evolved over time to meet the threat posed by the west and they have achieved their goals with new radar and sensors and weapon systems offering an interwoven defence network where even if a part is destroyed, the rest can still continue to operate.
Now that the INF treaty is gone the EU will realise what they need is an IADS like the Soviets and Russians have been developing for half a century or more to protect them even just from cruise missile attack.... cruise missiles are cheap to mass produce and most importantly the ones the EU wants to protect itself from are not the expensive precise missiles coming through the third window on the right in a HQ building in Brussels... what they need to stop is the much much cheaper one with a 200KT warhead that might miss the building by 200m or so but will still obliterate the entire city block and several more around it... much cheaper and simpler and with breeder nuclear reactor power stations much cheaper and quicker and easier to equip with a nuclear warhead...
They are going to need the cheapest gas supplier they can find...