P.Tsunami said:
First of all, define "clone". I'm assuming you don't mean a game that is entirely identical to what it's copying, because I have yet to see that in any genre.
you evidently haven't bought a "198 games in one"GBA pak abroad have you? i'll give you an explanation. there are approximatly 5 true games in there (such as in mine, i have FF4, Pokemon Sapphire,Ruby&Emerald and some other game i can't remember). the remaining 193 games are either original (but crappy) arcade style games named after popular titles (such as pokemon Yellow, a game where you are a yellow Jigglypuff fighting in a side-scrolling fighting game... quite funny in the sense of jiggly-puff beating up other creatures, but not really a game) or they are copy and pastes of old games, such as Super Mario bros. or Dig-dug or that one about the miner.
These are what i would call true clones. sure, they have the decency to dress up, changing Mario into Sonic, or Dig-dug into Samus, but the levels are exactly the same with the same principles... sonic didn't run any faster than mario did, nor did he curl up in a ball when i jumped. these are what i would class as clones.
anyway, that was really offtopic, i agree with your points and you have phrased them the best of out the posts i've read so far. Many genres, such as FPS's, have to borrow and apply aspects from other known titles in order to get any body to play them. a popular (and stereotypical) example nowadays would be that nobody is willing to buy a nowaday FPS where you don't have regenerating health and you can carry more than 2 weapons at a time. very stereotypical, but sadly, the FPS producing companies seem to belive its true.
i haven't played much of half-life, but i can say that i saw quite a few similarities between half life and Bioshock. the most obvious one to me would be that the way the crow-bar and wrench are held/used in both games remind me of each other... but i wouldn't say Bioshock is a clone of Half-life (anymore than i would say Battlefield is a clone of Modern Warfare).