Some bad comparisons as mentioned by others.
None of the listed American target ballistic missiles are directly comparable to DF-21 ASBM variants, let alone DF-26. DF-17 is a boost glide HGV... completely incomparable to MaRV DF-21 and DF-26.
Intercepting standard MRBM and IRBM even ICBM are things US, China, Russia (USSR actually) could do and very much likely have done many decades ago. After all, programs for ICBM interception in these countries have existed since the 1960s for the US and USSR and since the 1970s in China. As we know now, agreements between USSR and the USA on ABM were worth nothing.
The thing is, intercepting MaRV is nothing like intercepting pure ballistics. Sure SM-6 most likely can handle MaRV with ease. If I were a Chinese planner, I'd automatically assume SM-6 in ideal situations not only has 100% performance against MaRV weapons in my arsenal but has decent capability against HGVs already. (Hence China's already got next generation DF-27 HGV in service as an anti-ship glider weapon according to leaked US intel that made the rounds).
The conflict between ship IAD and anti-shipping is really in how the attrition balance works between China's ability to saturate fleet defences while defending all its offensive assets and maintaining its long range kill chains for as long as it is required to deplete US fleet defences. Throw EW into the mix, all along multiple dimensions on both sides.
While HGVs and MaRV anti-shipping may not be silver bullets scoring 1:1 or even slightly less favourable hits, they do have an amazing ability to erode and challenge fleet defences... not to mention deplete interceptors at a 2:1 exchange.
All the pacific war scenarios are a matter of multi-layered attrition, right down to energy calculus.
In any case, the US as far as it is known, has not got a single HGV in service or HGV target platform to practice against**. MaRVs? sure, I'll assume that is a given. US counter to Chinese A2AD ASBMs and HGVs no doubt emphasise kill chain erosion over interception. Intercepting HGVs in the conventional way is very difficult even if you know the exact target. The best mathematical "method" for interception physics can easily be tweaked to engage HGVs and I would doubt China and US have not long already done this for HGV interceptors. Hence US military and thinktank open discussions on defence against HGV circle around focusing on kill chains and novel methods such as proximity based material clouds to damage HGVs and/or disrupt communications between HGV and guidance networks.
China has been testing HGV interceptors ever since fielding first generation HGV weapons. Assuming HGVs perform some wide approach arc AND is also capable of performing many slightly smaller radius turns before terminal phase, all an interceptor needs to do if it knows the target (which in this scenario, it would) is program the missile to engage the HGV within its terminal phase only or ignore HGVs turns and avoid draining its energy on "chasing" constantly varying interception points (a problem that more or less doesn't exist against ballistic only). China though, has many tricks up its sleave as the physics of all this is rather accessible even to the most basic engineer. Relying on HGV for anti-shipping would not serve as the ultimate and only "high tech branch" modality in its A2AD inventory.
We know all PLAN, PLAAF, PLARF platforms, weapons and networks exist and function as a brute force, integrated attack structure. In combination, they are far greater than the entire sum of individual parts, which by themselves already present untested and unknown threats against USN fleet defences. In combination, the risks are absolutely intolerable to the US without groundbreaking changes in weapons technologies.
The US even with its civilian leadership arrogance (contrasted with military leadership weariness) is concerned that not only is this the case, China's MIC especially in the domain of A2AD, is evolving and improving at a faster rate than US ability to guarantee military primacy in western Pacific. DF-17 is but the tip of the iceburg serving as China's high tier A2AD... DF-27 HGV perhaps on the waterline of "mysteriousness" if western intelligence has a thorough understanding on DF-27 military exercise shooting and related observations, all being considered a low level security leak.
Truly what China doesn't talk about and what is shielded from US intel gathering would be China's own methods of eroding the range and extent of US kill chains and of course eletromagnetic and cyber domain warfare. Pushing through those intangible fields = even your YJ-8s scoring hits.
**HTV2 was a pure study based vehicle and not as impressive as America stronkists say online. I mean ffs China was test flying HGVs back in the 2000s as well. Never made such a big deal about it with visuals and photos for public consumption like US non-black projects always do even during their study and test phases. Practically speaking HTV2 is NOT a target HGV for interceptor practice. Perhaps a variant can be or has been developed for target practice purposes but given the cost of each one as demanded by defence contractors, the US military would maybe only have purchased a few for modelling. The issue is HTV2 could have very different flight characteristics and turn/evasion programming to develop decent enough models to optimise SM-3,6,x against Chinese HGVs.
All a long way to say in summary the US does not have decent and tested direct interception means against even Chinese MaRV ASBM in networked, saturation attacks against fleet defences. Chinese A2AD would have to let USN fleeting within first island chain to maximise the use of all available anti-shipping forces many of which are coast based. This range is still far away from the max combat radius of F-35s and F-18s. The US sending B-2s and B-21s escorted by F-22s alone on missions to erode China's coastal arsenal is a suicidal gamble. Ergo, the US would have to deal with the entire Chinese arsenal performing saturation attacks that when timed in waves, are many times greater than fleet defence interceptors (not counting CIWS), assuming US can knock out many Chinese platforms like H-6 and various fighters while eroding Chinese kill chains, that's still more missiles headed for carriers and warships than USN can reliably guarantee against.