I think you're underestimating the cost of leaving Google Photos.
Sure, it's not too bad but I need to migrate off a new platform literally 5 years of photos (+ face tagging), explain it to all my relatives, make them install another app.
Or I can just start paying 2$ per month.
I'm not too bothered but it's a clear bait and switch.
To be fair I wasn't sure if this was coming or not given Google is not exactly a small business and could afford to spend some storage money to lock people in better in their ecosystem.