The default assumption should be that the solar system is typical and that would lead to numerous earth-like planets in the galaxy and that would give hope to a

The default assumption should be that the solar system is typical and that would lead to numerous earth-like planets in the galaxy and that would give hope to a lot of (intelligent) life. But untiol a few years ago, this was just a very plausible explanation. Since then we have confirmed thousands of planets. So while there are still a lot of unknowns for a good prediction, the planet count is at least consistant with the assumption, that solar-like systems are not an exception.