alt Hacker News> at ten cents I can hand a student a part they are allowed to destroy. [...] at a dollar a part a teacher flinches
Ah, I think that explains my confusion (in a different top-level comment[0]).
I read the wording in your article as you getting shipped "a dollar worth of chips" or "a dollar of chips", which to me sounded like you were talking about ordering multiple chips. So I assumed that the per-chip cost for ARM and RISC-V were close enough not to matter too much, and the shipping cost easily dominated.
But now I see it says "one dollar chips" (either I read it wrong initially, or you've updated it since I read it), which makes sense. $1 vs. $0.10 is a big difference at even smallish quantities. (My assumption was that the chip cost difference was more like 1.5x, not 10x.) And while the shipping costs are huge enough to dominate regardless, being able to order 10 chips vs. 100 chips for the same price (and presumably roughly the same shipping cost, even if it is high), is a big deal. The "allowed to destroy" bit is very real.
I thought your argument was about shipping costs, since that's what you focused on so much in the article, but the real issue is still the cost of the chips themselves. The ridiculous shipping cost you have to pay is certainly a factor, but I think a teacher in China would still flinch at giving a student an easily-destroyable $1 part, vs. a $0.10 part, even if their shipping costs are basically nothing.