Land can[not] be held with smaller, faster, more agile (and cheaper) [disposable manned targets].
Today's modern, cheap, plentiful and easy to use air-to-ground missiles and shoulder-fired rockets make an Abrams tank as disposable as a Toyota pickup.
Here's the NATO FGM 148 Javelin:
https://www.youtube.com/watch?v=6qHL7jET8Gc
And the equally effective Russian Kornet, just one of several ATGMs in their arsenal: