Nokia did the „stupid” things only when their business was already collapsing due to Symbian, not the other way around.
Took them around 4 years from iPhone’s premiere to get to that point. And I remember people saying that Symbian’s user base is too big to fail even weeks before the WP announcements and later up until the burning rig memo.
Ditto Blackberry, although blackberry had a shorter history at that time.