I think the trick is to get the car moving even slightly while steering to drastically reduce steering effort.

There's also a corner case - winter driving conditions - where manual steering might give you lots of critical feedback.

(that said, I wouldn't purposefully get a manual steering car anymore)

Also before powersteering manufacturers had to do a compromise between ease of use and available grip. Parking a car with wide tires such as a 70's/80's supercar was a real workout. Hence many cars of that era without powersteering had narrowish tires and thus very poor available grip and emergency braking efficiency.

Powersteering has allowed cars to have much more available grip and it is not a inherently a bad thing although it comes with its downsides too. Mainly fuel efficiency and overconfidence issue.