There are numerous references to aliens (angels/extra-terrestrials, nephilim) and UFOs in the Bible. The visitation of Lot by two angels who then destroyed Sodom and Gomorrah, flying chariots of fire, wheels within wheels, star of Bethlehem stopping directly above a manger in Bethlehem, pillars of fire in the sky, John's vision of the New Jerusalem as a city (we'd probably call that a mothership these days) descending from the sky, etc. Even Jesus reportedly said:
John 18
36 Jesus answered, My kingdom is not of this world: if my kingdom were of this world, then would my servants fight, that I should not be delivered to the Jews: but now is my kingdom not from hence.
Which is literally "my kingdom is extra-terrestrial", meaning he (the spirit inside the human body) was/is extra-terrestrial. It is of course a matter of one's perspective, but it is impossible not to see Biblical mention of ETs if you are conscious of the ET question and read the Bible without organised religion blinkers on.
I don't just want to point that out. You did ask about consequences and later stated that all religion will pass away some day, so here's my take on it. One needn't exclude the other. Theoretically, one of the consequences of mass contact could be truer religion, as certain myths were dispelled, and the difference between science and the spiritual becoming less pronounced. Even without direct contact, the spiritual (some of it) could well be scientifically proven, once scientific knowledge reaches the necessary standard in order to scientifically verify it. Any organised religion which runs counter to this revelation, would then likely pass away, but any true religion would remain/be amplified. At the same time, wrong or bad science would also pass away (or things that currently pass for "science").
If someone already believes they aren't just human, and suspect they may have an extra-terrestrial Creator, their religious belief may not change as much in that respect, as long as ET contact reveals itself in that manner. If ET contact happened to be in a different manner, then obviously it will alter things. I do think all organised religions will have a hard time, no matter what method of contact. So will concepts (beliefs) like money, politics and statism, suffer. These too, are religions, from a certain point of view, requiring belief in their authority and their value, in order to have any value at all, or at least as much value as we currently place upon them.