Why is that relevant, you ask? Well, AM will (hopefully) continuously renew itself and its strategy in order to keep earnings high, whereas the hardware simply gets outdated and earns progressively less and less as time goes along. So: buying hardware may earn you more in the short term, shares in AM may earn you more in the long term.
Comparison is NOT faulty. It is a comparison of "investment" (whether in hardware or a company) and "return" (whether mined bitcoins or dividends paid out as bitcoins). I think most people will agree that the value of hardware (GPU or ASICs) will generally depreciate over time, so that is a "known." The big unknown is AM, which as you point out is a company. We hope they will continuously renew itself, but anything can happen.
First, let me apologize to all the other readers of this thread for harping on about this.
Secondly, I guess "value" is a very subjective notion and I am perfectly happy to agree to disagree on this.
Furthermore, I agree with you that the future is uncertain - also with respect to AMs future performance, it is by no means guaranteed that it will continue to be successful.
But the difference between AM and a piece of hardware is that AM is capable of strategic adaptation. I concede that a specific piece of hardware may outperform AM for a short period (your example arbitrarily showed one year, and I suppose that is OK for your purposes, but my horizon is longer). Beyond the very short term, however, the capability to adapt becomes more important: in three years the piece of hardware you purchased today will continue to hash at 5 GH/s regardless of what the network hash rate is (i.e. essentially earning very low returns), but at that time I expect AM has expanded and evolved way beyond what it is today and continues to rake in large profits.
It is uncertain whether or not AM will still be raking in huge profits in three years. But I can guarantee that your 5 GH/s miner will be more or less worthless at that time.
Those are just my thoughts, and anybody is of course welcome to disagree and invest as they see fit, focusing on the time horizon or risk profile that fits their personal taste. So now that I shared that, I will stop harping on about it - back to your regularly scheduled programme...