It wouldn't surprise me if people typically use more storage on their phone than their computer. The phone should probably have a higher base storage than the base storage of their laptops.
Extremely interesting point. My initial reaction to your comment is that it is a crazy thing to say, but the more I think about it the more I agree with you. On my phone is where I have tons of 4k 30/60FPS videos, high resolution photos (with live), and videos downloaded on Netflix and YouTube.
On my Mac I don't have any of these things, it's mostly for programming and some packages. I'm almost always connected to Wi-Fi (except on planes) so I don't really need any photos or videos.
The only people that I see have high storage requirements on Macs are probably video/media creators? As a programmer I'm totally fine with 512GB, but could probably live with 256GB if I wanted to be super lean.