Should have said that when they started coming in.
They (well, Germany and just about everyone else in Europe) never grasped that there was no border and no stopping of the ‘walkers’.
Once you get to the Greek mainland....it’s roughly six weeks of walking...a bit less if you take an occasional bus, a taxi here and there, and a train through Serbia and Austria. All you need is compass, a smart-phone, a water-bottle, and some rain-gear. Figure roughly 300 Euro for food and water....camp out under the stars....and just keep walking along the trail. They even built a trip-adviser-like software that gives you tips on what to do and where to sleep overnight.
They can talk all they want....but US-border rules apply (there is no border). Presently, millions are looking at the success of the past two years and figuring it’s time to make their walk into the ‘promised-land’.