Even with my low hashrate and the risk of burning out my cards, it's worth it for me because I don't pay the electric bill.

I do pay for some things around here, and there will come a time (pretty much when ASICs come, and I have ordered one of those so I'm fine in that regard) when what I make in coins will not be worth it even with the electricity costs because I'm using my personal card and it could break or start to malfunction in the games that I play or I may be asked to pay part of the electric bill and that would put me in a position where I didn't care to pay that extra 5 - 10 bucks a month or whatever for my few dollars in coins. But that time has not come yet.

You also have to realize that as long as you pretty much break even, you can still mine. Most people made enough from their farms to pay for the electricity more than double, so they can still mine at a gain. It's not reasonable to turn off a card that might not have even paid for itself yet, just because it's only make a few cents on top of paying for the electricity bill. You are still making something... And the cost of coins fluctuates a good deal. You might mine at a loss for a bit and then start mining at a gain for a bit, back to loss, and so on.. yet overall always be making coin and in the end have a nice stockpile that is worth far more than you paid in. Bitcoin should also always go up in price over time, don't forget that.

You don't have to factor in the cost of your mining equipment once you are already mining, and if anything, if you do include the costs you paid then you need to keep them on as long as you can pay the electric bill and get a few more coins after that or you lose out completely.

I wouldn't tell someone that it was reasonable to buy new equipment in order to mine if that is what you are talking about. But that has nothing to do with why the total hashrate is still the same.

There is also something to be said about the ease of mining over using any of the Bitcoin buying services. The easy ones always give to a good deal less.