Part of what we do is give users a path of adoption. For instance, routes will continue to work forever. The openshift routers have almost every bell and whistle possible for routes - and we've recently added ingress support. We also took all of the security features of routes and applied them to ingress - for example, if two different namespaces ask for the same hostname with a route, the oldest one always gets served. We also adapted the security rbac around routes to ingress, so you can set a role that controls whether end users can use custom host names or custom certs. We also are in the process of adding all of our extended cert validation to the router for both routes and ingress, so if a user puts in a bad cert other users aren't impacted.

Basically, you can use vanilla Kubernetes if you want. But openshift is a sundae with sprinkles. Come for the ice cream, stay for the toppings?

Edit: also, every add on in openshift is either something that will eventually be in Kube, or an extension to Kube. Red Hatters are the ones who added extensibility to Kube (with help from others) like api extensions, CRD, initializers, web hook extensions, binary CLI plugins. We did that so that OpenShift can extend Kube to solve real user problems, and also so that everyone else in the ecosystem can do the same.