I think it's important to put this into context, because although 2017 doesn't seem that long ago, this was over five years ago and the political climate has drastically changed since then. Donald Trump had only been president for about half a year, but with somebody with those views on race in power it's not surprising that people like this were beginning to feel empowered enough to try to organize themselves. I think the worst omen of all for the future wasn't that the Unite the Right rally took place, it was the fact that the president of the United States repeatedly refused to condemn one side of the protests more than the other, pretending like it was a case of "both sides are equally bad". This makes it seem like white supremacy is just a standard political ideology that should be accepted into society for the purpose of maintaining discourse and freedom of speech, not a disproven and completely illogical way of viewing the world. I think, given this, it's no surprise that there has been a rise in Neo-Nazi violence since 2017.
I think the events of Charlottesville are, as has been said several times, the result of an "Us" vs "Them" mentality, but I feel like a lot of emphasis should be on the "Us" part of that. People enjoy being parts of things, they relish in the camaraderie of movements like this, even if they don't fully agree with all the values shared by those around them. The Unite the Right rally appealed to right wingers because it sounds alluring to meet other people who share your political beliefs. Sure, you think, they might have some beliefs that seem extreme, but they're welcoming me into their community with open arms, so what they think can't truly be that wrong, can it? Ultimately, this is what causes people to fall down the rabbit holes of white supremacy and Neo-Nazism, and fundamentally altering their worldview.
I wouldn't just say that something like this could happen again, I am nearly positive that something like this will happen again, maybe very soon, or maybe closer to the 2024 election, when political tensions are higher. We've seen the anger exhibited by these extremists continue to rise as time went on, and basically nothing is being done to stop it, so why should we expect it to just magically disappear into thin air? I don't know what's going to cause the next Charlottesville or January 6th, and I don't know what's going to happen as a result of it, but I feel confident that it will occur.