Mas has liked the M-14 platform for decades, so I do not see his article as shilling for SAI. I highly respect his choice, for an oatmeal-hits-the-fan rifle.
The troubles of 2020 did prompt me to add an LMT 20” 5.56 AR upper, with a twist rate suited for 77-grain OTM bullets. That helps with velocity, for long-range performance, but, it is still 5.56 NATO, so, not anti-material, with motor vehicles being the material, in this context.
I purchased a small but meaningful quantity of Federal Truball Penetrator 12 gauge slugs, in 2016, in anticipation of the 2017 Stupid Bowl, as I knew I would be posted at one of the barricades. This was a time when terrorists in Europe were using stolen truck to mow folks down, and, my Brenneke hardened slugs were a number of years old by then. Of course, this is a close-range solution, and, as Mas’ article indicated, one has to feed a shotgun early, and often, if things get really nasty.
I have two Browning BLR lever rifles, chambered in .308 Winchester. One is a Takedown, which makes it pack-able, and, I could pack the Takedown, in taken-down mode, while carrying something else in my hands, or on a sling. The .308 Winchester gives me reach, and the ability to affect things that are inside vehicles.
I have a Winchester Model 70 Safari Express, .375 H&H, which could really mess up material things, but, like the shotgun, it requires feeding, early and often, if facing a horde. My .375 H&H ammo is quite old, by now, and I never accumulated much of it, but this cartridge has escaped much of the panic-buying, so is still available, locally and from on-line sources. I may well buy some fresh .375 H&H this week.
An M1A, or other “Main Battle Rifle,” would give me the ability to combine some features of each of my above-mentioned weapons. The two specific rural places, to which we would go, if we had to hunker-down outside of the Houston, Texas metro area, are heavily wooded, which lessens the need for long-range cartridge performance, so, if I wanted to spend ~$2K at a local gun store, I am not likely to be using it to add an M1A. (IF any are in stock!)
My most recent serious “tactical” training was with one of my Benelli M2 shotguns, and I have familiarity with the Benelli platform that dates back to the early Nineties, with an HK/Benelli M1 Super 90. The Benelli M2 is a light-in-weight weapon, which is good thing, with a couple of age-related upper-body physical issues. So, if I had to exfil, on foot, from an area, I might want have a Benelli slung, or in my hands, for close-range emergencies, and either my Takedown BLR, or an AR15 with my LAW-folder-ed lower, inside a pack. My Eberlestock pack is sized to internally and discreetly accommodate a folded 16” AR15.