- The IDF might spread itself too thin but I'm not quite sure that's a concern for them.
- "Their rapidly crumbling international support" Let me know if Turkey or Egypt is included in that claim.
- Is the correct reason.
Gaza is one of the densest urban areas in the world and is currently occupied by a demonstrably well organized and committed defenders, who have had decades to prepare. On top of that, IDF infantry was proven to be surprisingly ineffective in 2006. Conventional military wisdom is to level the city to the ground, like Raqqa or Aleppo, instead of doing an infantry invasion. I doubt they have any plans to actually invade until Gaza is leveled.