Classic "I've a nail so everyone will have nails and all they need is a hammer" attitude. Not everyone will use DHCP. Static IP is a thing for a reason. I use it on servers, Wi-Fi printers (for mobiles to immediately pick them up), IP packet logging/bucketizing based on client, etc. There's a lot of spheres in computing other than the end-user one which is just the final tip of the iceberg.