Not sure if this is still the case but in some areas Comcast used to limit the cap to 100gb unless you bundled TV with your internet plan, then it went up to 1tb.
This is still the case in the Houston Tx area. I am paying 50 extra bucks to have "unlimited" internets because kids. We averaged 7 days before our 1TB was used each month.
That, and other resources tend to get compressed less as bandwidth and storage becomes cheaper overall. Less compression means less load on already underpowered console hardware and more importantly, less memory used, high end games tend to max out their IO and outright memory map things straight from the disk.
GTA V on last gen was notorious for reading off the optical disk and HDD simultaniously to spend less time moving things around in memory.
Disk failures are a major reason for performance degradation on consoles and why putting SSDs into consoles is a very good idea.
We recently started using XBox Gamepass which is a small monthly fee to get access to a fairly large variety of games (all digitally downloaded) and our bandwidth usage exploded b/c there's no extra charge to pull down 5 games that maybe looked interesting but that you would never pay full price for.
The HDD bloat really stuck out to me when I looked at the upcoming WoW Classic Requirements - the current game requires 70 GB of space, but Classic requires 5GB. All games, even old ones trying to stay modern, require a huge amount of space.
I have about 150 games downloaded to my primary console. Not all of them are that big, but a good number of them are huge. Looking at my firewall logs, it's pulled down 400GB in the last 30 days. I've only installed one new game in that time. Updates for huge games can also be huge.
Also, things other than my Xbox Ones use bandwidth. They are just the largest single consumer of it.
We have 7 people in the house and I can breakdown the usage like this:
Mac sync between 5 machines (this was surprising to me)
Instagram/social(I thought YouTube would be 2nd place)
YouTube
Netflix