Possible, but this is a sweeping statement. Don't laugh if you don't mean it, it's so ficititious. Real debates never have people laughing, it makes them look like fools. I have never loss anything from resale. So far, my net profit is about $450 SGD. It's like buying stocks. For all lenses. You just have to know what you're doing if you choose to buy and sell often. If you don't and you make a loss, it's your own damned fault. I may be Stoned, but at least in my state of stupor I debate in fluent English.
This is again a hasty generalisation. This depends once again on your ability to monitor the market and Buy and Sell at the right time. You misread me, for I never said that you must sell your new lens at a higher price or without a loss. I merely said "Would you expect, using your critical faculties if they exist, him to be able to sell a used lens at a new price?" because you said "Another friend bought a 3rd party XXXXX lens, use it for 7 months, tried to sell it here unsuccessfully for 2 weeks.. until he lower his selling price to 65% of the new price. See the point ...?". The fact is that there is no point here to miss, other than the bad grammar, because you are comparing the sale of a 1st hand and 2nd hand lens. By the way, before you say it again, it's REPUTABLE.
Hasty generalisations abound everywhere here. The price that you can sell at is not fixed but is determined by consumer demand, amidst other factors, which you would know if you studied basic economics. How come i never try desperately to sell a lens? Odd. OH I KNOW, well perhaps you should consider carefully and do your homework before buying the lens in the first place! Well, gee whiz! What a great idea! Only buy a lens if you need it. Who on earth buys a lens to sell? Even someone like me whose equipment cycles around very often buys a lens to use.
Suggesting that you can only make "nice" pictures from an L lens is a cardinal sin in my book. Guaranteed to invite flaming, which you are getting now in a generous amount. What do you say to a photo challenge then, my Sigma 24-60 Vs your Canon 24-70 or 24-105 or 28-70, whatever strikes your fancy. I've currently no other 3rd party lenses, more's the pity, else you would be able to see what third party lenses can do in many other ranges. From the way you talk about the glass, you obviously spend more time fondling your phallic symbols than actually making pictures with them. What you said about Ls instantly causing you to make "money-making pictures" is not valid. Flat out. I'd like to see you do it if you think I'm wrong. Oh, and why are you sending in your 3rd party lens for calibration checking? Perhaps because you were foolhardy enough not to test the lens at the store itself? Likely scenario.
Tell me what is mediocre about a particular piece of glass and I will go out of my way to prove you wrong. Compare apples to a similar fruit please. Don't compare a 70-200/2.8L with a Sigma 55-200. Compare a 70-200/2.8 with a 70-200/2.8. L with EX, SP, etc.