I've probably mis-formulated those paragraphs as they're consistent with one another. What I've meant under "botnet operators don't have to earn a margin" is that in case of virtually zero monetary costs (leaving out opportunity costs) they don't have to cover those to still profit. Opportunity costs only move the decision point for the botnets to exit XMR somewhere earlier.
In terms of economic decision making, opportunity costs are usually equivalent to monetary costs. If you can rent your botnet out for $X per day (or do something else with it to earn $X), then it makes no economic sense to mine <$X per day of anything, you are better off renting it out. This has exactly the same effect on decision making as monetary costs of $X/day. More than $X of mining, you mine, less, you don't.
Logically the argument of not having to earn a margin just doesn't make sense, as described above. There is revenue level below which it makes no sense to mine, above which it does make sense to mine. This applies to every botnet and every other type of mining equipment.
This also applies to BCN or any other coin (at least the ones with mining, but especially CPU+GPU coins with limited captive investment). Yes BCN has lower rewards (proportionate to coin supply at least) but it also has much lower difficulty, so you can mine proportionately more of it with the same equipment (botnet or anything else).
Honestly I don't really see much difference between XMR's price action any just about every other coin. It goes down when nothing is going on (and coins which have nothing going on for a long period of time eventually go down to near zero). When there is some sort of development that sparks speculative interest, it goes up. Look across the spectrum of hundreds of coins and you see almost exactly the same pattern. Who mines or whether they are a botnet or not doesn't really seem to matter much.
