The tablets were never meant to survive. They are unfired clay records of palace administration, listing rations, livestock, textiles, personnel and offerings, kept for a single year and then discarded, and they exist only because the fires that destroyed the palaces baked them hard. The religious content is therefore incidental: it appears because temples and sanctuaries received allocations that had to be recorded. The names in those allocation lists changed the study of Greek religion.
Zeus, Hera, Poseidon, Hermes, Artemis and Dionysus appear in Bronze Age records, some five centuries before the earliest Greek literature, which established that these gods were worshipped in the Mycenaean world rather than being later arrivals. Dionysus in particular had been widely treated as a foreign import of a later period, and the tablets made that untenable. They also record deities who did not survive, along with a title meaning the Lady used with various qualifications and no certain identification. So the tablets both confirm continuity and show loss, and they say almost nothing about what any of these gods were thought to be, since an offering list records quantities rather than beliefs.