load on steering from braking?

Yes they wear out. R&P steering is simpler than recirculating ball but both take a beating from the loads on the front end.

that's all true but leaves out one aspect. Very little actual wear occurs simply because the bearing surfaces have "load" on them if they are just sitting there and not moving. Most of the wear is from those times where there is both load pressing the surfaces together AND movement causing the two surfaces to move relative to each other. When you make a panic stop there is a lot of load but unless you are steering wildly from side to side there isn't much movement of the surfaces. There's the front end dip when you first put the brakes on and that's about it. If you think of the parts that are always heavily loaded and always moving you wind up thinking of the "ball joints". Then think of the difference between driving on smooth roads versus rough roads. The rough roads put a lot more shock load on the tie rods as well as making them "move" up and down as the suspension bounces, then a smooth road does. So a rough road is going to wear out this stuff faster because the stuff is always moving up and down under load. That's one reason why "highway miles" are a lot easier on a car then driving around town.