It’s a forcing function for an upgrade. You pay 75% of the cost of the device for each 2 year cycle and many people will keep doing that in perpetuity. Compared to someone that keeps their phone for 6-7 years, the leasee will pay 3x as much over that 6 year period. Apple will also get the phone back and resell the refurbished one for 50% of its original price.

Apple will benefit in two ways. They will make 125% of what they used to make on every phone they sold because they can sell it twice and more people will be forced into the two year upgrade cycle (because they can’t afford the buyout at the end) increasing their overall sales numbers in general. If you’re a consumer, you should just treat this as a 24 month interest free loan and then buy the phone outright at the end of that period. If you put the outright cost of the phone into a bond (say 7.5%) during that period, you will even get 3 months payment free and only pay for 21 out of those 24 months.