The problem with this line of reasoning is the old saying "He who wants to defend everything defends nothing". That is, you simply can never have enough troops to garrison the coastline from Bayonne in SW France to Nordkap in Norway to an adequate level to ensure a defeated invasion. Especially if your are fighting a two-front war already, soon to be a three-front one. Nor can you have enough coastal batteries every few kms to cover the entire coastline.

By the way, these photos of mighty batteries are very impressive, but in fact how many were they? And what if it was dark, or there were any fog, what use would these batteries be?

Of course, not every single km of coastline would be sparkling beach sand, quite a lot would be totally inadequate to land a force on, but anyway of those left it would still be impossible to defend every single yard. So the solution was as Rundsedt said to keep mobile reserves back. However Rommel's argument that the interdiction capabilities of the Allied tactical air forces would keep these away from battle had a reason to be, so the Germans certainly were in a dilemma.

To add to the confusion, what if all the hints point to invasion coming to a specific place, it is expected at that place, and all reports start coming from what appears to be a diversion further southwest? This is what happened.

The Gröfaz should have kept to his watercolours and never meddled into wars, this is what he got himself into.

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