The Apple Upgrade lease model isn't even a replacement as you have to wait 24 months before upgrading.
The entire point of the iPhone Upgrade Program was to make it painless to swap to the newest iPhone every year. Without that, there's no value proposition.
They have 12 month options for the Apple Upgrade program. I just checked how much it would cost to get an iPhone 17 PM + AppleCare+ with theft protection like I currently get from the IUP and it's $3 more a month.