I don't know anything about Intel CPU manufacturing, but it actually did occur to me that since the N2830 is so similar product when compared to N2820 it probably is cheaper just to produce N2830 and sell them for every use that requires either N2820 or N2830. That way you avoid extra storage, logistics, etc. costs. Note that also N2810 has been discontinued with only months in production.
It's quite often the case that these auxiliary costs exceed the actual production cost and thus it does not make sense to have two products active on the line that are too similar.
Have a look at this article regarding the terminated Bay Trail products: