"It's pretty hard to fail to make sense of it...
If batsman gives chance, you'd normally expect it to be taken, yes?
What does the batsman do differently when a chance is caught and when it's dropped?
Answer: nothing. Nothing whatsoever.
So therefore, as far as an anaylsis of the batsman's ability is concerned, a dropped catch and a caught one are the same.
Now then, it needs to be understood - getting the end of a finger on something is NOT a dropped catch. No fielder has ever caught a cricket ball without at least getting it into the flesh of the fingers. Therefore, hitting a ball into a fielder's fingertips is NOT giving a chance.
With slight rephrasing, the same can be said of a batsman getting out (caught off a think nick\glove that the Umpire doesn't spot, pretty plumb lbw - not something HawkEye suggests is grazing the top of leg - clear catch turned-down by Third-Umpire becuase he's 99.99% not 100% certain about it, etc.) and being given not-out.
Equally, if a batsman clearly gets a shocker against him (lbw to a ball pitching a foot outside leg, caught behind when he missed it by daylight, etc.) then he does not deserve to go, no? Indeed he doesn't. So we credit him with a not-out. This also applies if his partner sells him a dummy with a suicidal run.
Common consent is that these things even each other out. Anyone who has taken any note whatsoever of the reality of the situation will realise that this is complete and utter bull****. Virtually every batsman has more good luck than bad in a career - but some are luckier than others (in my time watching Gilchrist was incredibly lucky for a time, Hayden has been very lucky for much of his career, Trescothick is surely the luckiest batsman EVER, and Sehwag, especially when facing Pakistan, has been lucky beyond the bounds of decency). Another common misperception: ah, I spot a link! They're all hard hitters! Well, yes, but so are most of today's batsmen. The truth of the matter is most of these dropped catches have been sitters at slip and in the deep, not balls slammed at close-in fielders.
So therefore, to get a fair interpretation of the performance of a batsmen, we simply count a chance as the same regardless of whether the fielding side \ Umpire was good enough to take it. And we don't blame batsmen who get unlucky for their misfortune. "