It may be a matter of opinion, but if a driver doesn't have the ability to drive safely (i.e. defensively, with concern for others, etc.) without the use of the guardrails (no pun intended), then they really shouldn't be driving.
Driving is a skill. If it requires "hacks" or mind games, then we're doing something terribly wrong.
Some countries that have implemented safe street design also have drivers who know their place on the road.
Safe street design won't have the same effect in countries where drivers feel entitled and for which their behaviour has no consequences.
For example, we have stop signs and red lights. Everybody who drives should know what they mean.
But we have the majority of drivers rolling through stop signs, and quite a few ignoring red lights. You can't really design this stupidity out. Roundabouts are not an answer when the attitude of entitlement still exists. We are just shifting the bad behaviours to another part of the road.
And in particular Ontario, where our government would rather build wider roads with fewer safety implements, makes this challenge even more difficult. Drivers need to change their behaviour, and need to, well before we make the roads "safe by design".