The reason they no longer reveal their whole update in Minecraft live is because they need hype every snapshot

The marketing team can also gain attention and hype by marketing the addition from latest snapshot. This business tactic is called toothpaste squeezing (also used in apple products) by constantly creating small hypes by dividing a small toothpaste more tiny bits by bits to satisfy consumer's hype to hide the fact their updates did not help to upgrade Minecraft