Given that Apple are selling iPhones with 1TB of storage these days, you'd expect them to test the ability to import huge libraries. (even if the 13 Pro still uses USB 2.0 so the transfer speeds would be abysmal)
I don't think it was using iCloud. It would show up in iTunes (haven't used my Mac much since iTunes got split up) and I could drag files around from some applications and back it up to my local drive (in addition to the iCloud backups).
If you started on iOS in 2010 and kept all your photos, this is hardly an edge case. People take a crazy amount of photos nowadays, definitely not unique to photographers.
I think the majority of people don’t copy photos from their iPhone to their laptop at all.
Firstly, they may not have a laptop. Secondly, I expect many more of those who have one will sync photos from their phone to iCloud and from iCloud to their laptop then directly from their phone to their laptop.
Yes, for large archives, that costs money ($10 a month gets you 2TB if iCloud storage), but I guess/think the convenience and having almost direct backups in case you lose your phone are worth it for most people who want to do such copying.
Hardly seems like an unusual situation. I suspect most people never import photos from their iPhone, they might have quite a few if/when they eventually choose to do so.