This is one of the few remaining unposted remnants from Magus Firecow (aka Ka-Ming Lin).
I had a pun about this that’s too terrible even for me to tell, Jedi Knight, anyways…
So there’s this huge period of time when there were no new Jedis strong enough in the Force for Yoda to train. Many many years he was stuck on his tushie, essential an unemployed Jedi Master, with nothing to do except wait and wait, while his planet slowly precessed into one big swamp. Can you imagine him there, just sitting and watching another Dagobah.