I don't think it really matters what caliber the weapon comes in -- the United States Army goes a poor job teaching soldiers to engage targets at 300 Meters and beyond, let alone farther against a moving and turtled-up foe.
I would beg to differ on the point of infantry. You may control the sea and air, but land is controlled by people. The Straits of Malacca have to be held or controlled by soldiers on the ground. Naval, air, and logistic ports and bases are secured by occupation forces or otherwise affected by commandos, partisan-guerrillas, and saboteurs -- as history has proven.
Artillery and drones inflict over 80% of the casualties on both sides in Ukraine. They're trying to kill humans (the infantry).
If it isn't for those pesky humans an invading power could just hoist its flag and say, "This is now mine."
I think we’ve reached a point, like has happened several times in history before, where a particular innovation significantly changed tactics and made certain trends obsolete. Breech-loading firearms allowing soldiers to go prone, ironclad ships that made wooden ships obsolete almost overnight, repeating firearms that allowed unimaginable volumes of fire, aerial reconnaissance, the telegraph, submarine, airplane, tank, machine-gun, etc.
If we assume similarly-equipped dismounted infantry forces who both have UAS with FPV-targeted munitions that can drop a small mortar round-sized warhead on individual soldiers in fighting positions or on the move, it makes zero sense to employ Infantry against Infantry unless you just want to waste bodies.
Even if we seize objectives and key terrain, buildings, blocking positions, whatever, those forces will be vulnerable and attrited unless the enemy’s ability to project UAS and artillery on them is destroyed.
The way we fight already at big picture FSCO level is with air power in the lead, destroying all the POL, airfields, munitions storage facilities, cratering runways, taxiways, parked aircraft sheltered or unsheltered (to include heavy, medium and rotary wing lift aircraft), EW aircraft, tankers, AWACs, SAM sites and their Radars, perimeter defense Radars, C4ISR nodes, power stations, intersections, bridges, logistics chains, rail yards, etc. etc.
So if we come out of the gate doing that, there is no real way for any threat infantry to deploy, project their limited force (including UAS), get resupplied, or establish any type of credible threat. Any maritime troops caught out at sea will have multiple anti-ship weapons targeting them, including a new JDAM quick-sink mode that is a software upgrade to the existing JDAM, no hardware. That’s on top of all the LRASM anti-ship missiles we already have, which are stealth missile bodies with multi-mode NAV and targeting in denied GPS environments, with threat node avoidance, and resulting extremely-unfair pk. Stuff that is far-superior to what India just used against Pakistan to shut down their air bases overnight.
Those Chicom troop-carriers and tank-landing ships would be some of the juiciest targets for every attack submarine Captain, USN & USMC Fighter/Attack Squadron in-theater as well, so the maritime force projection platforms we’re seeing from the PLN is really strange, unless they have a friend in the WH and Taiwan Presidency simultaneously.
The brutal humiliation China would face in FSCO would make Desert Storm look like a picnic. There would be no way for them to move armor or infantry units in-theater once the airfields and ports are shut down. This is without even discussing the air threat and OCA executed by numerical and qualitative superiority from US, Australian, JADF, and ROKAF 5th Gen fighters.
Everyone likes to look at numbers of the US only, without counting all the PACOM partner nation fighters and naval assets. Japan, as one example, is on the books for 400 late block RGM-109Es Tomahawks.
Even if they initiate with a massive Cyber War attack against the US Mainland and PACOM bases, baseline capabilities still run without that. Assuming Cyber and even 25% attrition against our air and sea assets, the airfields and ships still all get hit with the same numbers of weapons because of how redundant the targeting is with weapons allocation across the partner nations and US services.
This is before we even talk about US Army and USMC Long-Range Fires.
What I could see is for all the artificial islands they built, whatever hold-outs they have at each of those islands would need to be policed-up, but you can just let them starve after DEAD-ing their SHORAD platforms. No reason to waste US or coalition lives fighting them directly on the ground. Literally let them starve if you don’t want to cluster munition them, or bathe them in CS for a while.
This is why I suspect China will do everything in their power to trigger another 9/11-style event that will distract and waste US combat power somewhere else in the world, as far from the Pacific as possible. Then we can talk about Infantry, but when I run through the strategic-level events for FSCO with them, I have a hard time seeing how Infantry even gets to the fight across the distances involved. It would be a strategic mistake to deploy infantry for them in that type of environment, where air transports that might make it off the runway fly deeper into a mesh of weapons that mean nothing but flaming scrap metal descent for the entire aircraft and its occupants.
Notice I’m not even mentioning US armor in this mix because I just don’t see any role for it, and the USMC was wise to shed themselves of the M-1 Abrams albatross for all the reasons above. If we’re not even seeing a place for armor, then dismounts with small arms make very little sense.
I’m willing to see different perspectives and modify or abandon my assertions, but I really struggle to see what ground I would even want to take with Infantry in the above strategic developments. When I was in South Korea in an Air Assault Battalion on the DMZ, the plan was to move us south once we saw NorKs marshaling anyway, because the DMZ was going to become saturated with artillery and long-range fires, primarily targeting Seoul. Our ISR assets since the 1990s have evolved dramatically to have more foresight into strategic marshaling, so it makes sense when that unit was moved back to Campbell (flagged). We didn’t really have a mission then in the big picture.