Why should anyone expect to see any POTUS' tax returns?  There is no law that says the president has to reveal his tax returns.  Tradition isn't law.  I think it is more appropriate to expect a POTUS who has been a politician all his life--living off taxpayers--to reveal his tax returns than it is for a POTUS who was a businessman and worked in the private sector.   FDR didn't release his tax returns, and he came from a very wealthy family.  The "tradition" didn't even start until Nixon.