Those kind of tricks are basically risk mitigation against untargeted attacks or attacks targeted against components that can be damage limited. They're fine for that. They fall short when attackers start aiming for the hypervisor, firmware, etc or can do damage within the compromised VM/partition (app-layer attack). Security against those attackers has to somehow isolate the effects of their data or code from those things. In other words, you need it at every layer with each component assured and the integration done safely. None of those meet that. Only one's that come close are commercial and might not even serve a small business. :(

My old strategy was several cheap computers hooked up with a KVM switch and a guard to assess data moving between them. Basic airgapping w/ trusted transfer. The simplest scenario splits confidential and untrusted (esp Internet). Wasn't that hard to use: just inconvenient on occasion. Setting up guard and software properly is tricky to say the least. A specialist is necessary although an OpenBSD or Linux box well-configured can work out for common attackers.

On Windows, I used AV for reaction, Defensewall/AppGuard/SandboxIE (varied) for prevention, did backups/restores with a boot CD, write-protect BIOS if available, regular patching, and Linux Live CD (kept up to date) for stuff like banking. Regular restores from backups, too, with patches applied to clean copies. I used RAMdrives for temporary storage so it autodeleted upon shutdown. I used write-protect HD's to prevent corruption of OS partition but not available now that I know of. Physical wire, not wireless, for Internet disconnected in old school fashion when not in use to deny bot bandwidth if nothing else. :) Non-traditional router made from non x86 or ARM box running a Linux or BSD firewall distro. Sparcstations with OpenBSD were popular among paranoids. Can't remember mine as it was one time.

Just a few things I remember. Had I stayed on Windows, I was going to next explore using Windows Embedded to strip out more attack surface. A friend named tommy, smart but not IT guy, systematically backed up, deleted, tested, and restored on failure his Windows XP box in iterations until he found how little code & data it needed to still function. He got a WinXP system with Office, Firefox, AV, etc down to 650MB total backed up on a CD. Unreal. I figured, as I had stripped 'NIX's, I could apply that strategy to Windows with more ease if I let Embedded's tools safely do first stage for me. Good head start cuz I don't have years of obsession for one hardening. ;)

Also, on lighter side, I put some people with extremely minimal needs on hardened Mac's with PPC processors. I knew malware authors would exclusively target Intel's upon the transition with replacement hardware cheap on eBay. Strategy still works for those using it. One of my air-gapped backups is a PPC laptop I got for $80. What do RaspPi and accessories cost again to deliver what? ;) Otherwise, hardened Mac's on Intel might be a safe strategy for average business due to rare targeting. Even Krebs endorsed that strategy at one point. Still with backups to read-only media and such. So, there's that.