Either they would have arrived already (and taken over the galaxy, suppressing us in the process) - or they have yet to arrive. The chances of them initially showing up around about now are going to be pretty small.

They apparently haven't arrived here already - unless they seeded us originally - else where are they? So, if they are out there, they have yet to arrive.

I don't really see how all this makes much difference to the original argument.

The point of that argument was that seeing yourself alone in the galaxy with no aliens around is only to be expected - if the first intelligences rapidly expand and suppress the subsequent development of other intelligent life. So, being first is not so much of a miracle.