I understand your concerns but you can run the unit for long time like 5 years and add bits of BTC together. If you dont hurry, it can return your BTC in my opinion
The estimation is outright dumb.
Here's the evolution of mining tech:
1. CPU's - "everyone has them - but not so many people know about mining"
2. GPU's - "just a handful at the start, insane success, more people get involved" - you could still get profit even half a year after 7970 released to public.
2.1. FPGA's - a beast that only matters when you're limited by power (cost/availability)/thermal package (you plainly can't put 100 7970 into a small room) - otherwise the cost is on par with GPU's or higher.
3. ASIC's - again insane success at the start - but watch the dumbasses that have no understanding of what are they doing: doesn't matter what the hashing power is but you still get 6 blocks/hour distributed among all the miners.
3.1. "first generation of ASIC's" - like Avalon - low-end tech, insane success for Avalon and first owners. 66GH/s is still comparable to what was owned by miners (ah, ok, 20+ times more than I had). But GPU's still bring almost the same US$ they did a year ago.
3.2. "newer tech ASIC's" - similar numbers but lower power usage.
3.3. more investments and running towards the bleeding edge in lithography - with the potential of getting a lower cost, lower TDP and an order of magnitude faster units at the same time. But - this is almost the end of the technology race, after this point the situations like "for $1500 you get what the others have for $15k" will not be possible. Meaning not a "dead halt" of course but a serious decrease in hash rate GROWTH.
Remember, we still get 6x25=150 coins/hour?
W/o exchange rate growth - first-gen ASIC's that were obtained at the end of the summer/in autumn will not even bring their USD value back. Let alone BTC value. We know nothing about how long the units will be in working condition as well.