Why does Telemachus doubt that it is indeed his father, Odysseus, who he sees enter the swineherd’s hut?

The reunion between Odysseus and Telemachus is very moving. Odysseus, still in disguise as a beggar, meets Telemachus in the swineherd's hut. Athena tells Odysseus it is time for him to remove his disguise and reveal his true nature to his son, so she waves her golden wand and returns him to normal. Odysseus tells Telemachus that he is his father, but Telemachus cannot believe him. After so many years of waiting for his father...

The reunion between Odysseus and Telemachus is very moving. Odysseus, still in disguise as a beggar, meets Telemachus in the swineherd's hut. Athena tells Odysseus it is time for him to remove his disguise and reveal his true nature to his son, so she waves her golden wand and returns him to normal. Odysseus tells Telemachus that he is his father, but Telemachus cannot believe him. After so many years of waiting for his father to return, Telemachus believes that one of the gods must be playing a trick on him. He exclaims:

You are not my father, but some god is flattering me with vain hopes that I may grieve the more hereafter; no mortal man could of himself contrive to do as you have been doing, and make yourself old and young at a moment's notice, unless a god were with him. A second ago you were old and all in rags, and now you are like some god come down from heaven.

However, Odysseus reassures his son that it is indeed he. Thus reassured, Telemachus embraces his father in a very touching scene.

Nevertheless, the reunion between Odysseus and Telemachus is also ironic. As the royal family, the king and prince should have reunited in the palace, surrounded by great pomp and splendor. However, this king and prince reunited in a servant's hut!