What factor limits the number of galactic civilization assuming that the conditions ripe for life and intelligence abound in the Galaxy?

Answer 1

I would say the limitation for galactic settlements would include:

1. lack of billions in dollars for funding to build space rockets
2. extreme distances to other planets
3. unknown safe routes across those distances
4. inability to sustain life en route to other planets
5. lack of oxygen on other planets
6. lack of plant life
7. lack of a transfer of C02 to O2 to a cleaning cycle or method which plants and trees give us earthlings
8. lack of correct temperature for earthings to live on other planets
9. and IF other civilizations exist, it is likely there could also exist multiple languages, so language barriers could be a problem.