In one lecture, Srila Prabhupada spoke about this potential jiva. Prabhupada said that it is not only that the spiritual master has to be bonfide but also the disciple has to be bonafide. By that he meant the disciple should be willing to accept the gift the spiritual master is bestowing. So it is natural to be curious to want to know who will accept this gift and who will not? or rather what is the qualification to accept the gift of the spiritual master?
I was reading the purport to CC Madhya lila 19.152, in there we get a clue. Below is the short excerpt.
Those with a background of pious life are eligible to receive life’s supreme benefit, and to bestow this benefit, the Supreme Personality of Godhead sends His representative to impart His mercy. endowed with the mercy of the Supreme Personality of Godhead, the spiritual master distributes the mercy to those who are elevated and pious.
Here in this purport, Prabhupada qualifies a potential candidate of mercy is one who has a pious background, those who are elevated souls. To say this the other way, those who have whole-heartedly accepted the gift from guru (guru-prasāda), we can say are actually the pious souls. They must have performed sadhana in their previous lives to accept this gift in this life. I also want to distinguish mundane piety (in the name of dharma, artha, kama) from piety being referred here. Mundane piety leads to mundane prosperity (not certainly Krishna). Pious means one who has performed practical service to fulfill their constitutional positional as a servant of God.
So yes, Krishna consciousness is certainly not for everyone. Only those with a pious background, those who are elevated will be able to fully accept guru-prasāda and make tangible strides on the path of ananya bhakti towards Krishna - the primeval and original living Being!