People do not know about their real home in the spiritual world.

Generally people are not aware of their interest in life–to return home, back to Godhead. People do not know about their real home in the spiritual world. In the spiritual world there are many Vaikuntha planets, and the topmost planet is Krishnaloka, Goloka Vrindavana. Despite the so-called advancement of civilization, there is no information of the Vaikunthalokas, the spiritual planets. At the present moment so-called advanced civilized men are trying to go to other planets, but they do not know that even if they go to the highest planetary system, Brahmaloka, they have to come back again to this planet. This is confirmed in Bhagavad-gita (8.16):

abrahma-bhuvanal lokah punaravartinorjuna
mam upetya tu kaunteya punar janma na vidyate

“From the highest planet in the material world down to the lowest, all are places of misery wherein repeated birth and death take place. But one who attains to My abode, O son of Kunti, never takes birth again.” If one goes to the highest planetary system within this universe he still has to return after the effects of pious activities are finished. Space vehicles may go very high in the sky, but as soon as their fuel is finished, they have to return to this earthly planet. All these activities are performed in illusion. The real attempt should now be to return home, back to Godhead. The process is mentioned in Bhagavad-gita. Yanti mad-yajino ‘pi mam: those who engage in the devotional service of the Supreme Personality of Godhead return home, back to Godhead. Human life is very valuable, and one should not waste it in vain exploration of other planets. One should be intelligent enough to return to Godhead. One should be interested in information about the spiritual Vaikuntha planets, and in particular the planet known as Goloka Vrindavana, and should learn the art of going there by the simple method of devotional service, beginning with hearing (sravanam kirtanam visnoh). This is also confirmed in Srimad-Bhagavatam (12.3.51):

kaler dosa-nidhe rajann asti hy eko mahan gunah
kirtanad eva Krishnasya mukta-sangah param vrajet

One can go to the supreme planet (param vrajet) simply by chanting the Hare Krishna mantra. This is especially meant for the people of this age (kaler dosa-nidhe). It is the special advantage of this age that simply by chanting the Hare Krishna maha-mantra one can become purified of all material contamination and return home, back to Godhead. There is no doubt about this.

Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Fourth Canto, Chapter 29 – Text 48