You can't be serious when you suggest China would lack projects to spend money on!
Compared with the USAF, the PLAAF has a gap of some 500 air transports and 450 tankers. The PLAN has a gap of some 600 tactical fighters compared to the USN and another 150 in EW fighters.
And what would China do with 500 large air transports?
The US military is designed for distant power projection globally.
However, China's core interests are in the Western Pacific, next to China's coastline.
This will only change once China has built up a Navy which can contest for control of the broader oceans.
And this will take a minimum of another 10 years.
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A similar calculation applies to airborne tankers, where heavyweight fighters taking off from mainland China can easily reach Taiwan or Korea. It's really only Japan and potentially the Philippines which are at the limits of fighter range, plus operations against the US Navy. I would think an absolute maximum of 1000 sorties per day would be required or is practical, which would require around 250 tankers.
Then compare this to current production rates of the Y-20, which is 12-24? per year. Presumably this is all the MRTT variant which can undertake both the Tanker and Transport missions.
If Y-20 production was doubled, assuming 12 per year, an extra 12 Y-20 would be $1.8 Bn per year.
If we assume Y-20 production is currently at 24 per year, an extra 24 Y-20 would be $3.6 Bn per year. Even this figure would only account for
1.4% of a $260 Bn military budget increase, assuming it went from 1.7% to 3% of GDP. Yet producing 48 Y-20 would mean it only takes 5 years to reach the previously mentioned 250 tanker requirement.
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So in summary, there are 2 main points:
1. It would be nice to have more tankers or transports sooner yes, but there comes a point where you build up a huge supply chain and production capacity, only to have to shut it down very quickly. And you don't actually shave off many years in terms of acquiring the capability you're looking for.
2. There is no need for China to increase its military spending from 1.7% to 3% of GDP. Even an increase from 1.7% to just 2% would mean an extra $60 Bn per year. Roughly speaking, this alone would be enough to double Chinese military procurement rates. Hence my view that from a national security perspective, if you had another 1% of GDP available ($200 Bn per year), you're better off using this for the dual-circulation strategy, which aims to cut Chinese dependency on foreign imports, make the world more dependent on China and also build up world-class Chinese companies in literally every industry and sub-sector. This will also provide more jobs and economic growth.
In terms of submarines, the gap is between 40-50 SSN/SSBNs.
China has 0 long range strategic bombers and no current way to reliably and sustainably strike CONUS with conventional weapons.
PLA missile inventory is a bit opaque but a 10,000+ cruise missile inventory like the one the US is building now would be most necessary.
Cost out what you are suggesting.
China is currently at 3 SSNs per year. Roughly speaking, we see a pattern where Chinese naval ships cost half that of the US.
So even assuming a doubling to 6 Type-095 SSNs per year, that only comes to $12 Billion per year, which is less than 5% of a $260 Bn budget increase, if military spending were to go from 1.7% to 3% of GDP.
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China and the US are simply too far apart for long-range strategic bombers to reach other.
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The US is going with large numbers of long-range expensive cruise missiles because it has no choice.
There are only a handful of floating airbases (US aircraft carriers)
Plus the US only has access to a small number of land bases, all of which could be expected to come under continuous attack. All of Japan is within 1300km of mainland China, which is within range of heavyweight air superiority fighters and affordable missiles. Even Shaheeds costing $20k? can launch from China and reach Japan. In comparison, it isn't credible for the US to launch larger numbers of equivalent munitions, given that the Chinese military would likely be capable of blockading of Japan for example.
Plus we can see that China isn't going with cruise missiles but hypersonic missiles.
Again, work out what 10000 missiles like the DF-17. would cost. Over a 5 year production run and assuming a cost of $2Mn, that would only be $4 Bn per year. Yet this would be so much overkill given that Chinese aircraft can follow up on an initial missile strike and also launch cheaper missiles/drones afterwards.
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NB. I've mostly omitted operating costs because they aren't too relevant to the analysis.