Both things are sort of true. Its not sales where size can hurt you but retention, which is why it tended to matter more on phones. When you need space on your device the apps are listed from largest to smallest.

On both phones and PCs storage has just grown so its less of an issue. The one thing I have noticed is that Apple does its price windowing around memory so you pay an absurd amount for an extra 128 gb. The ultra competitive Chinese phone market crams high end phones with a ton of memory and battery. Si some popular Chinese phone games are huge compared to ones made for the iPhone.