I didn't realize that the esc key was gone before I ordered my new 15". I haven't had a "touch bar" model yet. Why didn't the touch bar take off with developers

I didn't realize that the esc key was gone before I ordered my new 15". I haven't had a "touch bar" model yet. Why didn't the touch bar take off with developers? I read Apple said you can develop functionality into apps to utilize the touch bar. Why didn't this happen?