Do you also study linguistics or just teach? Also, have you studied Esperanto?

I’m referring to 16 years of experience teaching language and seeing where the pain points were in acquiring English from Mandarin speakers.

So anecdotal evidence. I'd like to see if any other linguistics teacher has the same or different opinions.

Also, your evidence is from Mandarin speakers; what about European speakers, or African speakers? Your assumption should apply to Mandarin speakers then; because otherwise you just assumed that Esperanto wouldn't be more difficult than English for other unspoken groups (like the Vietnamese and African)

It's kinda important to get anecdotal evidence with other groups so that you don't make a hasty generalization.

Would Esperanto be easier than English to learn? Of course! It's far more regular than English. But the point here is that while easier than English, it's not much easier than English because as a language at a conceptual level it is not that different from English.

Concepts aren't the only factor that influence difficulty. Conceptually, glass is easy to make when learnt; but it is hard in practice to initially make glass, because the human body lacks experience. Likewise, English might seem easy to conceptually learn; but the English orthography can make English hard to speak, especially when there are letters that can have the exact same sounds as another letter (like C and K).

And then on top of that the consonant clusters (thank you Polish!) would render it nigh-impossible to pronounce.

How so? What's wrong with consonant clusters? English has them (such as c).

When that stark calculus is presented, the choice is clear: spend the little bit of extra work it takes to learn English and ignore Esperanto.

Or: Learn Esperanto anyway to make communicating easier for the rest of the world that doesn't speak English. (6.5 billion) There's barely even a cost to learning Esperanto.

I’d be very interested in seeing your mentioned studies, incidentally. Specifically seeing who performed them (and what their methodology was). My guess is that they weren’t professional linguists, and nor were they particularly rigorous (using things like self-selected subjects, etc.).

and do you have any studies supposedly showing the negligent difficulty of English and Esperanto?