What makes you think that "there will still be people on the earth after "one is taken and one left"? After every person is either taken or left, in other words? That is not what Jesus taught.
People need to remember that there is more to what Jesus taught about these things than just what is written in Matthew 24. Both Mark 13 and Luke 21 have further insights into His Olivet Discourse that are not found in Matthew 24. And there are also passages like the following where Jesus talked about things that He also talked about in the Olivet Discourse.
Luke 17:32 32
Remember Lot’s wife! 33 Whoever tries to keep their life will lose it, and whoever loses their life will preserve it. 34 I tell you, on that night two people will be in one bed;
one will be taken and the other left. 35 Two women will be grinding grain together;
one will be taken and the other left.” [36] [
e] 37 “
Where, Lord?” they asked. He replied, “
Where there is a dead body, there the vultures will gather.”
Notice what Jesus indicates will happen to those who are left behind and not taken. They will be dead. Killed. Feasted on by the vultures. So, with this in mind, what people exactly will supposedly still be on the earth after "one taken and one left"?