I just realized something. As I have mentioned in the past, this weeks parasha, Tetzaveh is the only Parasha outside of the book of Genesis to not once mention the name of Moses. God may be speaking to Moses, but we don't know from the pshat, from the plain text (except for the fact that "Aaron your brother" is mentioned and the anonymous recipient is mentioned in the masculine). All we have is the strange oddity where it constantly states "ve'ata", "and you". God instructs to the second person to make various vessels and vestments for the priests.
It immediately raises red flags that Moses, who for all intents and purposes is the main character of the Bible, is not mentioned by name here. I think, based on no extant parshanut, that God is talking to us. We can speak to the priest and exercise some control. A caste system has never really been a solid thing in Judaism. Sure, a Kohen and Levi have various entitlements in certain communities, but they also have responsibilities and burdens to bear. They must bless and serve the people Israel and for that we give them these entitlements. Synagogues that don't do Duchanen, the priestly blessing usually don't give the Priest and Levite the first two aliyot. In the ancient Land of Israel, priests were not allotted land and lived off donations from the people Israel. Kohanim today find it difficult to be rabbis or doctors (eliminating two forms of nachas for Jewish mothers) as priests cannot be anywhere near dead bodies, something incompatible with the position of doctors who save lives (and lose some) at hospitals and rabbis who offer deathbed support and officiate at funerals. It was not in fact easy to be a priest.
According to Mishnah Yoma, which I studied last semester, In the Second Temple, the Kohen who was "lucky" enough to be elected High Priest tended to die within the year after they served if they were not pure of heart. When the office became corrupted under Hasmonean and Roman administration, and the office was bought, High Priests died left and right. They cannot be in it for themselves but are servants of Israel and God. They are empowered by the Beit Din of the Sanhedrin and their position can be revoked, by monarch or by God (usually from the latter involves death or sudden disqualification). Next week and three weeks from now (as Maftir Shekalim) we will read the beginning of Ki Tisa where the annual half-shekel tax is announced. Though minimal so that even the poorest can easily afford it (the Half Shekel in Israel is roughly 11.5 US Cents), the priest has to remember who is signing their checks: the People of Israel. Therefore the Priest is answerable to them.
Rabbis too are not the ultimate authority. Any layperson can do anything a rabbi can. Sure, the rabbi is further educated in Jewish law and a rabbi is empowered and recognized by the state to perform legally-binding status-changing ceremonies such as weddings and divorces but really anyone with the know-how can do it. Everyone matters. YOU tell the Kohen what to do!