There shouldn't even be a discussion of h20 or jhxx. both are needed and both have their role. Range is important and 2000-3000 km combat radius is always welcome but even within the 1000 km there's plenty of potential targets. Actually, most of targets would likely be inside 1000 km. Right now PLAAF has no real means of successfully performing strikes versus an US like opponent that far away on a regular basis unless A) they're done with stand off weapons (too expensive to be the main weapon type and certain target types not efficiently engaged by such weapons) or B) there's significant numerical superiority involved (unlikely and features possibly unsustainable losses in the long run)
Whilst I agree that the H-20 is definitely needed, I disagree on the requirement for a JHXX. I'll just boil it down to the most important arguments:
For land targets <650km on the 1st Island Chain, you're better off with land-based missiles or non-stealthy aircraft, because the Chinese Air Force can obtain something close to air superiority and degrade the air defences.
The rest of the land targets on the 1st Island Chain lie 800km-1300km away.
Given the large number of F-35s and Patriot systems available, this means the airspace will always remain contested and the Chinese Air Force will only be able to obtain temporary air superiority and degrade the air defences temporarily.
You really do need to degrade the air defences if you want to use cheap munitions like the SDB-II
For example, an LD-2000 costs $5M and carries 8 short-range missiles and enough gun rounds for 48 engagements. It's probably uses something like a stinger missile which costs $40K. That compares to $120K for a SDB-II.
A manned fast, manoeuvrable stealthy fighter-bomber JHXX can be tracked with volume search UHF radar and also Infrared for fire-control.
So medium range air defence also means that the JHXX can't get close enough to use cheap munitions anyway, These 2 reasons means expensive powered munitions are required (maybe equivalent to a supersonic JASSM)
Eg. I don't have Chinese costs, but a block 3 Tomahawk launched from a TEL is sufficient for land attack and costs $1.4M.
An air launched land-attack JASSM has a much shorter range, but still costs $0.8M.
So each land-based missile would be $0.6M more expensive.
Whilst I agree standoff weapons are expensive, I think they are the new norm for both the Chinese military and US military. Note that the US Air Force is planning on buying 4900 JASSM missiles, so are standoff weapons (whether air or land launched) really too expensive?
And if you take a notional JHXX (FB-22 equivalent), it would cost $150M+, which works out to a typical lifetime operating cost of $450M+
In comparison, the costs of acquiring and operating an equivalent TEL system are much less. A Himars truck only costs $5M, so lets say $50M over a lifetime which is certainly an overestimate.
So a JHXX would have to launch over 600 missiles before the cost-benefit works out. Depending on your payload assumptions (2 or 4 missiles), that's 150 or 300 missions that a JHXX has to survive before it works out cheaper.
If a JHXX operates against a military peer, there is no way it will survive even 100 missions.
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For a JHXX or non-stealthy fighter bomber to deliver cheap munitions to the distant parts of the 1st Island Chain, requires air superiority. But that is a very long term goal which requires many more J-20s to be built first.
In the shorter term, better to go with land-based missiles OR use a H-20 which can get close enough to launch a lot of cheap munitions.
