I agree with this part:
It should be blatantly obvious to anyone with half a brain that there's going to be a lot less income from hardware sales due to competition. That same competition will also decrease AM's share of the network hash rate.
However, I believe most investors have considered it too (particularly those with more than "half a brain"), and that it is priced into the share price at the moment. There's no surprise that there will be competition. But AM has enormous competitive advantages - they won't be able to sell at 50 BTC anymore, but their process (130 nm) is most likely cheaper than all competitors, giving them better profit margins on their products.
So the current monopoly-situation will eventually end, but AM has everything it takes to compete head-on with the competitors (and win) when they eventually arrive.
I'm not saying that it won't be able to compete once the competition turns up. I'm saying that it simply won't be able to make as much money as it does now.