Was it really necessary for Apple to slow down old iPhones?

Was it really necessary for Apple to slow down old iPhones?  The Verge Batterygate: How Apple secretly slowed down older iPhones and why it's such a big deal  Business Insider How to check if Apple is slowing your old iPhone  BGR iPhone Performance and Battery Age - Geekbench  Geekbench Apple Sued Slow Your Roll ... Not Our Old iPhones!!!  TMZ.comFull coverage