The Vedic culture is a very scientific and precise science; science of the entire creation and the science of being as a microcosm of the macrocosm, which is the physically manifested creation. It very clearly lays down the path and also how to walk on it and provides tools and techniques such that the secrets of the creation are revealed to you; so that the final merger happens with full consciousness in a disease-free body… at will.
The reason why there are so many seekers and very few who achieve success is simple. Those who achieve success have three things in common – a Guru who has the traits of five yamas of ashtang yog, priority to the subject over other things in life and regular practice along with service and charity. The above three things are tied into the framework of four ashrams – brahmcharya, grihasta, vaanprasth and sanyaas. Each of these ashrams naturally flows into the next, it is not forced, the right practice of yog under a guru ensures this.
I will give a little insight into the vaanprastha stage for a yog-guru. Normally people think that it is renunciation, but there is no such thing as renouncing the world. One goes through it like a ship goes through the ocean, it is on the water and crosses the water, but is not in it and so it does not sink. Vaanprastha simply means to begin the process of limiting your interactions with the mundane aspects of life, and with people whose priority is not yog. In vaanprastha, teachings continue and interactions with sadhaks go on. It can be called that the ship is in the middle of the ocean and is moving towards its finality. Those on the ship are limited as only those who trust the ship fully are allowed. How long you have known the ship (guru) is of no consequence, your desire and other prerequisites are important.
Having collected the force within for the onward journey in the years of brahmcharya and having gone through the experiences of a worldly life as a grihasta, a being takes a step back from the physical world as he enters vaanprastha, because to reach the final destination, all this has to be left behind. For a rocket to break the pull out of gravity, it has to leave its excess weight. Leaving does not imply running away, the thought of the physical has to go.