A tank battalion is going to have N engineering and M recon units attached (values of M and N and specific makeup of said units varies by country and service). The point of "inconveniences" like barriers is to a) make the enemy throw an engineering unit at them thereby tipping you off to a probable attack buying you time to mass force there b) just choose to attack somewhere else that is more conveniently defensible for you or where you already have more manpower.

The neat thing about earth moving devices is that they converge at a time and place in a manner in which artillery and nearly any other conceivable weapon can hit them very reliably

> Dragon teeth alone won't hold against a tank for more than a few minutes

This doesn't seem accurate.

While searching for a video that shows a tank trying to go over (unsuccessful), I found a video showing three ways to get over them, and only the explosives would take a few minutes: https://www.youtube.com/watch?v=cRld768HDyc

Anchored concrete blocks can be made more difficult to move than the dirt under the tracks.