Tasker does not recognise incoming calls
The one you want is Event->Phone Ringing.  The State->Phone Call would not activate until you've answered the call.  Event Profiles activate and deactivate rather quickly so you probably wouldn't see it if you were trying to watch for the green active color.  However, you mentioned that it did not even set a variable through a test task.  Were you using a global variable for that or a local variable?  Try using the Flash action to flash the caller's name and see if that pops up.

Once you get that working and confirmed, you might need to do some more work on your announcement.  I'm guessing you're using the Say action.  You'll need to uncheck Respect Audio Focus in order for Say to talk over the phone ringer since the ringer takes precedence.  You'll probably also want to turn the ringer off temporarily using the Ringer Volume action to allow the Say action to finish and then turn the ringer back on.