Many people are also speaking very mechanically when they use a voice assistant, though ;) I believe we need a good mix, but telling people to speak a little more naturally certainly would help.
But you are right, the process has some flaws. Maybe we can review the dataset automatically on some common errors, once an STT system is ready for a language?
The only other option I can think about is a validation process that includes more people per sentence. Right now, only two people validate a sentence, and if they disagree a third person decides. We could at least double check sentences with one "no" vote one more time.
The app has a few nice features the website doesn't have, such as changing the speed during validation. It always surprises me as well, but many people hate to use web apps on mobile. I don't really know why, they simply ask for an app and refuse to use a browser.
Hey, I work on the Esperanto version of CV. You are right, many languages should be bigger than Esperanto, and we never planned to become this big, it just happened. We are around ten active people and a telegram group with a few hundred motivated donors. Plus, we write about the project in Esperanto magazines and talk about it on Esperanto congresses.
The point is: the only reason Bengali Korean and Malayalam are stuck "in progress" is that no one is working on them. No language but English is actively supported by Mozilla, it all comes from the communities. And the success of Esperanto shows that every language can make it. I hope that people take our work as a motivation. Every language can become big if a few motivated people work on it for a year or two. Even the smallest language can make it. You just need a lot of public domain sentences, a few thousand donors and some technical knowledge then your language will grow as well :)
You are not wrong, but besides the upper-middle-class hobby people, there is also a 130 years old culture that exists parallel to it. I've met a few native Esperanto speakers, and for them Esperanto is their identity. Traditional Esperanto clubs exists in countries like Iran, Japan, China, Burundi, Nigeria and many more. So Esperanto is both, a nerdy hobby and an old culture.