After getting into the higher worlds reserved for those of virtuous deeds, and living there for indefinitely long years, the one fallen from yoga-pursuit comes back to be born in clean, cultured and prosperous homes.
Religious thoughts and promises have, no doubt, an un-negatable place in the hearts of people. Knowing this well, Krishna casts his reply to Arjuna, so as to keep the pedestal of yoga and yogis far higher than that of religious votaries.
Even by dint of incomplete yoga-pursuit, the practitioner begets the higher worlds of the virtuous, for many, many years. The duration is limited for religious votaries, but not for the yoga-practitioner. He can spend countless years there, without any let or hindrance.
He need come back only when he wishes to. And when he descends, it will be to a very good family with sufficient culture, purity and prosperity. He will not have any struggle at all. A fortune many are not able to gain ordinarily!