I honestly don't understand why it hasn't happened.
I'd say it's honestly because of /pol/
After Charlottesville and Christchurch, the unironic far-right types have gone full-on "Have a nice pint and wait for all this to blow over" since they figured out the hard way what happens if you do "direct action" in the age of NSA supercomputers and militarized police forces.
The Left has a lot more leeway than the Right, obviously. But you can only go so far before you end up pissing off the wrong people and lose all the institutional backing you've enjoyed for so long.
Tellingly, the "Lock the doors, play vidya, have a pint and wait for all this to blow over" approach is the one thing that's universally agreed on in right-wing circles. Whether its /pol/, the Stormfag crowd, WigNats, Groypers, Proud Boys, lolberts, QAnon, and even typical Boomer conservatives, nobody's going to be the next James Fields.
At the absolute most, you'll see the Boomer conservatives do peaceful counter-protests with the local Proud Boys, Oathkeepers, or 2A crowd pulling security just in case Antifa gets too close and does something really stupid. Even then, they never use live ammo and just go for fists and blunt weapons and they almost never throw the first punch because they know the optics of it all and how the MSM will crucify them anyway but if there's no "Screw your optics, I'm going in!" antics on their part it makes the media look more hysterical and ridiculous.
I think they were counting on such an individual to make an appearance already so they can propagandize the shit out of it, but no dice.
There's a reason reasonable people are not engaging in direct action. We're not psychos. If they go too far, people will be lining up to go after them. But they're not there yet.
This. The vast majority of people are not true believers like the Woke Left typically are and they still have a shred of humanity in them. Even the true believers on the Right are not engaging in any direct action because they're being unusually pragmatic on this one and letting the Left destroy itself from within instead