Hmmm....
The detection of planets in "habitable zones" is a far cry from habitable planets. But maybe 1/1000 of these would in fact be suitable.
So then the only problem is that it would take five million years to get there.
So you see, it is not possible for humans to find other habitable worlds. But it is possible for the evolutionary processes of life to be spread.
It is still possible since the astronauts already found a planet like earth. If they were able to make a device that can travel that fast without carrying human beings then later on they will surely discover a new device that can travel as fast as the current device. Which can also load up humans.
If you study it, you will find that the requirements for life are so great that we will have to take everything along with us just to stay alive. The odds against life even happening here are so great that we don't understand how life could have happened. Colonizing other planets is way beyond anything we have a chance of achieving with any technology we have available now.
That is a great way of thinking, this is the only planet where the creator have given us and maybe that is really the reality that it is almost impossible to colonize other country