I think you could make an argument for the exact opposite. No, we have not reached the gifts my father or grandfather thought the internet would bring to society. For every hope that widespread communication would bring understanding among the populace and bring power to people instead of the elite, we now have a bot army or fake news infrastructure working to oppose those ideals.

But I think these problems, and the problems the author points to, are the result of the current, pre-internet world order attempting to impose itself on the modern web, not the other way around.

We've already seen the massive effects of the internet on the populace over the last 15 years or so, and I think a lot of those changes have been both quiet, and genuinely good for people (How many things are common knowledge now, that were never reported on the news, as a quick example?). What we're seeing now is the empire strikes back, as established organizations attempt to impose themselves back on this newly connected world before they go the way of the music industry. Whether this is done by manipulating people online, walling off sections of the internet, flooding the internet with propaganda/tracking/advertising, or simply removing the open nature of the internet in entirety (Net Neutrality), the drive appears to always be the same: large pre-internet organizations imposing traditional order on a new medium. And I think it is these efforts that are responsible for the majority of issues the author raises.

Though that's not to say the internet itself doesn't have a fair share of problems. But even where the internet seems at its worst, I think the problems still primarily come from traditional societal organizations, and it is they, not the internet, that should take the blame and be the focus of change. Let's take the surprisingly large influence of racism and fascism that appears to exist online as an example, easily one of the worst aspects of the internet.

I think prevalence of hate speech online exists for two major reasons. The first and largest driving force, is that the internet has revealed that outside of the internet, there are essentially no actually truly-free, anonymous, free speech places in a person's life. Even online, the number of places where one can state whatever they would like, to their hearts content, without having those thoughts potentially affect their daily life, are extremely rare and need to be sought out. Is it any surprise, then, that the people who seek out such forums are often those who are upset at the end of the day, and feel a need to spit some vitriol? Or that the users of such forums specifically focus saying things they know they could not say in any other aspect of their life?

I fail to see this as a shortcoming of the internet, and see it more as an indictment of society at large. Perhaps if there were more places where one can truly speak out at the end of a day, and be heard but not judged or discriminated against, less people would be willing to rage alone against an empty screen. But even if you reject this idea, then the alternative to me seems worse.
Because the alternative is that we have to accept that the average person is not capable, or should not be allowed, to navigate accountability-free communication, and society will need to be built accordingly going forward. Hopefully I don't need to point out the obvious downside to embracing such a philosophy.

That said, I think we did make, and are making one major design mistake, consistently online. And that is that we need to recognize that the way human society works, is that new ideas are shouted by individuals all the time, and then the silent masses judge them, mostly silently, and embrace them slowly into their day to day. On a webpage design level, this needs to be taken into account. If you are listing all comments on your webpage with equal weight, then we need to accept that you're going to get a pretty consistent distribution of comments ranging from insightful to hateful, and from thought-provoking to headache inducing. But if you allow the masses to weigh in, for example, by voting on comments, you'll find that most of the nauseating hate-filled ideas quickly fall off the radar, just like they do in real life. This is the difference between say, youtube comments and reddit comments. I would love to see websites start taking this a step further, and automatically start banning any users who are consistently voted beneath a certain threshold, just how in real life, everyone ignores the crazy guy on the sidewalk corner after his first diatribe is found to be crazy.