"I have almost 50Gb of free Dropbox storage btw, through referrals + events like the space race.!" which, I can assure you[0], the significant amount of Dropbox users don't have.
For cost comparison (UK pricing);
iCloud:
50GB: £0.79
200GB: £2.49
1TB: £6.99
2TB: £13.99
Google Drive:
100GB: £1.59
1TB: £7.99
So, Google wins on free tier, but Apple takes it on options and cost thereafter, and 15GB arguably is still insufficient for "OS storage" in any real tangible terms.
[0] no I don't have data. I do know plenty of Dropbox users though, and next to none of them have any extras.