I don't know if by "poor work" you mean a terrible topic to do a dissertation or the work itself (typing/grammer/language). Here are a few from the first category from the same year he wrote his thesis (2019):
PhD topic on "The Neverending Story":
https://dukespace.lib.duke.edu/dspace/handle/10161/18800
Did you read any of it? The "Neverending Story" bit is just a little teaser to get people to read, and the rest of the thesis has nothing to do with it. What we see here is a perfectly competent dissertation on the philosophy of language. They find some underexplored corner of semantics that they want to drill down on, operationalize it, and even perform some original research in support of their model by running survey experiments on Amazon MTurk to see how various phrasings and interpretations are received. I don't know that it'll revolutionize the world, but most dissertations don't.
If you look at the Matthew C. Harris dissertation, it's a mess. First off, the topic itself is ridiculous and racist. Second, while engaging with the existing literature is important, he spends an inordinate amount of time summarizing, rehashing, or even straight-up block quoting other writers. I'm too lazy to go through and total up an exact percentage of quoted/paraphrased verbiage used for padding, but there's quite a lot. The argumentation is also very loose - lots of reliance on "butterfly flapping its wings in China" and "can't step in the same river twice" concepts, which he then launders through another layer of "seems plausible", "would be consistent with ____" or "would be interesting". Take this random sample.
Recall that we do not actually see the environment, but as our brains expect them to be in the context the signals it receives. Therefore, it is not the fact that a person’s skin has any color that can make the color useful for visual tasks. Instead, one would need to learn to use that color in a way that makes such a response to it automatic. Such associations might be transferred implicitly like biases.
In fact, it also might be the case that other properties of visual cognition explain cognitive differences in cultural practices better than the literal interpretation of the color metaphors ‘white’ and ‘black’ in music. This is significantly more likely, given that skin color is but one of many visual factors that inform the visual perception of physical objects. So if the hypothesis of embodied cognition is correct, we might continue trying to think of perceived skin color as an optional resource to be deployed in the processing of other tasks, similar to the usage of one’s fingers for counting. This might be consistent with the findings of empirical studies on visual cognition that perceived attributes like color, luminosity, transparency and texture affect visual search and attention.
Look how many times words like "might", "would", "likely", and so on are used. Sure, it
might be the case that such-and-such is true, but if you're not going to provide any reason why we should believe it, who cares?
On the other hand, when he does go out and make actual assertions, they're not backed up by anything.
It would also be an overgeneralization to say that deaf Beethoven’s behavior did not involve any hearing of the music, since in all likelihood he still experienced the result of stimulations to his auditory cortex, even if they arrived from a different pathway.
In fairness, speculation about the inner workings of this 250-year-old brain seems to be a bit of a cottage industry.
He also leans heavily on meme theory (and, of course, lengthily quoting works by meme theorists) while
denying it, claiming that it's really just an interchangeable part which you can swap out for any metaphor you prefer - not that he proposes any alternatives. If it were true in any meaningful sense that meme theory is functionally equivalent to some other theory or family of theories when it comes to mental models, that would be worth a dissertation in its own right. As it stands, this is pure intellectual laziness at the core of his reasoning.
It's just not the case that everyone was doing work this bad.
