The Jewish priests in the time of the Tabernacle had to use the Urim and Thummim because they could not hear from God themselves. Moses could – all prophets could. Note that Moses was not the high priest – his brother Aaron was. They had separate roles.
They were the “Navi” (the Hebrew word for prophet) – an entirely separate group of people that often lived apart from people, sometimes alone in the wilderness. God could speak at any time, and they had to be ready. It was hard to integrate that task with “real life”. They were not provided for as the priests were. They did not receive the tithe as payment for their services as the priests did.
It is important to note the tithe in the early church was only used to help those in the community who were less fortunate – those who were sick or out of a job, or didn’t have family to help them. It was never intended to pay the salary of a priestly class, as there was not supposed to be such a thing. It was actually forbidden to have priests, as it created a separation in a Body that was meant to be One. We are all meant to be equal like siblings rather than have those who are higher or lower.
Even today, when a prophet hears from God and tells the priest (self-styled, for their authority comes from man and not God) they are ignored along with the message like many prophets in the past were. Of course they are – because the “priests” are incorrectly exercising control over the church. To admit that they are wrong would mean that they must get past their ego and let God be in charge – not them.