There is an interesting verse in the Padma Purana, where the Lord tells Lord Shiva:
tvam ārādhya yathā śambho grahiṣyāmi varaṁ sadā
dvāparādau yuge bhūtvā kalayā mānuṣādiṣu
svāgamaiḥ kalpitais tvaṁ tu janān mad-vimukhān
kuru maṁ ca gopaya yena syāt sṛṣṭir eṣottarottarā
“In the same manner, I shall worship you to ask a boon from you. You should descend to earth in your partial expansion and take birth as a human being in Kali-yuga. Concoct your own scripture and divert the people away from me. Hide me so that this creation will keep increasing.”
This is of course connected with Lord Shiva coming in Kali-yuga as Shankaracharya to preach impersonalism and thus bring the atheists back to the study of the Vedas. The interesting point in this passage however is the idea of increasing the population.
According to modern studies, the human population was much smaller in the past. According to such studies, there were just about 70 million human beings on the planet in 2000 BCE for example. In the last millenniums, however, the population increased exponentially, recently surpassing 8 billion. There are thus more than 100 times more people living on the planet now than four thousand years ago, closer to the beginning of Kali-yuga.
As this verse reveals, it was not by chance. There was a superior plan connected with that. Nowadays people tend to see the increase in the human population as a bad thing, but human life is something very important because it gives the souls the opportunity of remembering their eternal spiritual position as servants of Krsna. Instead of advocating birth control, as common in recent times, the Vedas go in the opposite direction, generally urging householders to beget children to increase the human population.
When we see from this optic, it’s easy to understand that the Lord desired to increase the population so more people would have an opportunity to take part in the sankirtan movement after the advent of Mahaprabhu.
People have free will, therefore some will join the sankirtan movement and others will not. The point is that with the increase in population, more of them are having a chance of doing so. We understand that devotional service continues and increases life after life, and therefore we can presume that people who start their devotional service in this life, even if in a very humble capacity, will continue practicing in their next lives, up to the point of going back to Godhead. Therefore, the quantity and quality of devotees on the planet will continue increasing in the next generations, up to the point when most people on the planet will be advanced devotees, preparing themselves to go back to Godhead. Because of their association, even staunch atheists will also have a chance of doing so.
Before Srila Prabhupada came to the West, the situation seemed hopeless. Now, however, the plan of the Lord is becoming clear. The population increased so much that people would have the opportunity to get in contact with devotees and transcendental books and thus make their choice.
When we see the problems that plague our spiritual society and the world at large it is easy to lose hope, but the ones who are more attentive can see the pattern of change appear. The sankirtan movement was practically unheard of in the West, and even in India things were not going well, with the collapse of the Gaudiya Math and the proliferation of all sorts of sahajiyas and other unbonafide sects. It didn’t seem there was hope for humanity at all.
Fast forwarding, 58 years later there are more than one million people who declare themselves part of Srila Prabhupada’s movement and are trying to practice Krsna Consciousness according to their capacity. This is even without including Vaishnavas from other lines, which also increased in number in the last decades. This is exponential growth.
Most of these devotees are still battling their conditioned natures and will probably not be able to go back to Godhead in this lifetime, but this is also good news because they will come back to continue their practice. As a result, the number of devotees in the next generations will continue increasing, as devotees from the past generations take their next births, and new people start their spiritual path, reinforced by people from previous eras and from the higher planets who, as described in Srimad Bhagavatam, will come especially to join the sankirtan movement. Taking all of this into consideration, we can be sure there will be some serious fireworks in the next decades and centuries.