Why wouldn't the Jerusalem believers have needed to sell their houses and lands?
Had Israel accepted the kingdom, the kingdom would have come in, bringing the utopia everyone seeks; the Jerusalem believers would not have needed to sell houses and lands or put everything into a common kitty. Because Israel rejected the kingdom, their kitty ran out and they became destitute.
Les explains that early in Acts the Jerusalem believers sold lands, houses, and whatever they had, putting the money into a common kitty so everyone lived on it; Acts 2 and 3 say they had all things common and no one lacked. But such a system exhausts resources, just as entitlement programs break a nation. That is exactly what happened at Jerusalem: they ran out. Had Israel accepted the kingdom, they would not have needed houses and lands; everything would have been the utopia people still seek. But Israel rejected the kingdom, so it did not come in, their kitty ran out, and they became destitute. God in His sovereignty still watched over them by moving Gentile believers of Paul's gospel to give offerings for the poor saints at Jerusalem.