If we know a Tzaddiks body after death does not decompose, why does the Torah record that Moshe took Yosef's bones to Eretz Yisrael? Shouldn't it have said Moshe took Yosef's entire body to Eretz Yisrael for burial?
תָּנוּ רַבָּנַן שִׁבְעָה לֹא שָׁלַט בָּהֶן רִמָּה וְתוֹלֵעָה וְאֵלּוּ הֵן אַבְרָהָם יִצְחָק וְיַעֲקֹב מֹשֶׁה אַהֲרֹן וּמִרְיָם וּבִנְיָמִין בֶּן יַעֲקֹב אַבְרָהָם יִצְחָק וְיַעֲקֹב The Sages taught: There were seven people over whom the worm and the maggot had no sway, and they are: Abraham, Isaac, and Jacob, Moses, Aaron and Miriam, and Benjamin, son of Jacob. Abraham, Isaac, and Jacob.
The gemara lists 7 people the worms didn't eat their flesh. ( Other midrashim have little diffrences, but Yosef isn't on any list. ) You can ask how come we find other tzadikim that their flesh was intact, while the sons of yakovs weren't. But the main point is, not all tzadikim have their flesh intact.