The most perilous form of reasoning:
"Carcosa, Lotfp, an so on. They were successes. But someone could simply say they would never have been without D&D.
Moreover, they "borrowed" mechanics from D&D, in some way or another they were "founded" on d&d mechanics.
In fact, really someone could have devised Carcosa without having ever read OD&D, Moldvay, or ad&d 1st ed.?"
Thank Heaven, i do not concur with the above argument. Nevertheless, it is enlightening to note that this is one of the reasons why many persons regard several other fantasy rpg's from the past as "petty" d&d spin-offs, a sort of sub-products of d&d.
The "perilous reasoning" is a simple and straightforward logical argument which would prove very difficult to refute if taken seriously.
But do we have to take it seriously?
The only way to refute it (thus showing that Carcosa, for instance, can rely only on itself and its merit), is to show a complete disinterest in finding an answer to the question put at the beginning of this post, because i think the question is based on a false presupposition.
Put simply and in a nutshell, the presupposition is that we are always, in each instant indebted to Dungeons & Dragons, we cannot get rid of it.
It is the big red flaming eye which is always staring at us, we can't escape from its sight.
A false presupposition because Carcosa and Lotfp deserve both their recognition as fantasy games, regardless of d&d. And even if d&d had never existed, i think it is likely someone would have concocted something like Carcosa or Lotfp sooner or later. I think the same for Arduin (i wrote a post about it some time ago) and for any other FRPG from the past.
The pernicious reasoning was detrimental in the past because it overshadowed many rpg's worthy of attention (and several ones possibly worthier than d&d itself).
As soon as a new fantasy rpg aroused they said: "it is just an alternative to d&d, with some rules modifications, that's all". Even when a game was born which was in stark contrast with d&d, they simply said: "it is a reaction to d&d".
So in a way or another they were almost never regarded as INDIPENDENT ENTITIES.
It is as if someone showed me a new animal from planet Venus and i couldn't but compare it to the terrestrial denizens i am used to, trying to highlight the similarities, instead of trying to understand it as it is, understand it as a new and different entity.
The perilous and pernicious reasoning might be a menace even nowadays, if only a large number of persons stood up uttering such infamous sentences as the one i wrote at the opening of this post.
I myself believe in the inner quality of both Carcosa and Lotfp, and i would like to hear everyone say:" those guys had never written a fantasy rpg before- howbeit, i feel their first attempt was quite good, up to the point i decided to abandon d&d in favour of their fantasy games".