Life and human intelligence hasn't only been around for a few thousand though... it's been a few billion for all life and 40-50k yrs for modern humans.

The fact the circumstances for intelligent beings took so long may have been random circumstance. There's no guarantee it would take that long on other planets to go from general life -> intelligent beings. The environments could easily be more welcoming to it, they may have had fewer extinction events restarting growth, etc, etc.