I'll keep this very brief --
First of all, Sikhi isn't a religion, it's nothing more than the path of Truth (to keep it in simple terms). In addition, I am not saying that other so-called religions are not true in some manner or the other.
Sikhi preaches nothing but the truth, it's true that there is reincarnation, though, what sikhi asks you to do, is realise that and realise "heaven" so what is heaven in this case? It is the state of you realising your-Self. Some people call it enlightenment... we'll go with that, no worries. And thus, get out of the cycle of life-and-death -- though even after you have gotten out of it, you may once again, chose to experience life again.
If all religions were divinely inspired?... They WERE inspired, and some folk didn't like that... blah blah -- in short, organised religion was born soon after the departure of the saints who "invented" the religion.
Back in the days, in the times of Zeus and the other Greek Gods, people have a huge curious taste about faith, what it really meant and what was looking after this world and all sort of crazy ideas which we today, intend to ignore. These people would spend time just looking at one leaf and trying to discover the mysteries about life etc.
Their thirst for knowing brought them to enlightenment, well some of them. Though, I doubt it was much talked about back then... the people who did get enlightened in some manner, did not even realise it, they took it as their feelings, or a trans state.
The truth is that, you have to remember who you are in this life which has been gifted to us, that my friend is heaven... so just like back then, ever one has the chance even know, to know God, but I doubt we listen.
People had various mythologies concerning the Greek gods, even the people themselves back in the time, some concluded that there is a higher force -- how to know it?
"ask and so shall ye receive" -- very true.
You know, we're very lucky to have Guru Granth Sahib, our Gurus took the effort to compile it for us, so that we may not be mislead, yet we still doubt it. What else can we expect from people who think such? To me, gurbani seems like a "code" waiting to be deciphered, and once it is... oi boy o boy!... ya, really amazing!!