And likewise if you throw a dedicated turn lane and some sidewalks at these roads they do a pretty ok job.

Absolutely not. If you're ever in Calgary, take a walk along Macleod trail near the Chinook centre. The sidewalks are filled with face-height street signage in the walkway, the sidewalks randomly venture between vehicle lanes, they'll sometimes just end, there are pedestrian road crossings without markings or signage, etc. It's one of the most unpleasant built environments I've ever encountered, up there with polluted Soviet mining cities.

I'm sure someone somewhere has managed to do it wrong but where I live it's done decently well and there's a fair number of main roads that meet the description I gave and are fine as a pedestrian, not perfect but fine.

Unprotected lefts have been widely recognized as one of the tasks that are especially difficult for autonomous driving to handle--which, of course, means that they can be relatively tricky for people too. And, yes, well-defined places to walk and cross streets help pedestrians--at least if they use those defined places which they often don't in cities.