I think in almost every real world scenario, the loop only runs once. I don't think it adds a huge amount of complexity to the layout algo - you still need to code in the loop body, even if you don't actually loop. That said - React Native only does two passes, and nobody seems to have noticed/complained.

You can do some neat things with the looping behaviour - like have a toolbar with some icons on the left and the right hand sides and a title centred in the toolbar - but then have the title move off centre as soon as the icons from either side touch it.