To me, "economic cost" is actual dollars. Selling a call and being called out on a running stock doesn't cost me actual dollars. It has a non-dollar cost I have to weigh for risk/reward, but getting called out subtracts no money from my account.
BTW, you're right in saying call sales hurt the company's valuation. Especially where there is growing short interest and heavy call writing, the market makers go short common to hedge the calls they buy.
About the only situation I can see where selling calls is going to lose you extra money is a very fast whipsaw move down then up. The down move sees your underlying common is taken out by margin call, stop loss, or manual sale. The up move sees the stock rising above your strike price + premium before you can buy the call back (or buy more common to cover). If there is a sector where that could happen, it is probably biotech because of the vol and propensity for trading halts on news. Come to think of it, this probably happened to people with the flash crash moments before the DNDN IMPACT data were released.
I also agree with you that people see covered calls as a hedge. They are absolutely wrong. Executed correctly, you can lose less money on a drop in the common. But they don't protect you from downside risk.
If one wants to be precise, and perhaps this is what you're getting at, you should actually size covered positions smaller than non-covered positions because you've limited upside reward and only partially reduced downside risk.
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