Reflecting on the 17th of Tammuz

The Mishna in Taanis lists five calamities of the 17th of Tammuz, including the broken Luchos, and among them the Korban Tamid being stopped. Why is that the one sacrifice singled out, when every korban ended? The introduction to Ein Yaakov adds a stranger piece: one Tanna says the single pasuk that contains the whole Torah is the one about the Tamid, next to Shema Yisrael and "love your friend as yourself." What did that daily offering hold that the whole Torah leans on? A friend's anniversary gift that cost far more than he ever saw her spend gives a clue.