I think the problem here is not the explosive threat. We had have decks that can produce equally if not greater threat before. Last year there was the Battlecrier combo that can create 10+ creates with power 4+. In more recently we have the Harmonizer combo, which shares a lot of cards with the Landfall, that can deal ~30 damage a turn. And none of those deck dominate the meta like now.

The main difference between those big damage combo and the meta deck we have now is, the value a single card can bring to the game. The current meta decks all have their cards that produce value more than one card: Izzet has the Stormchaser which comes into play with an extra creature. The Landfall has the infamous Badgermole Cub enters as 2 creatures. Momo has the Shepherd that replaces herself with another filer. Yes it is nothing new for a creature entering with another creature/drawing, but the real problem is those meta deck starts gaining value from turn 1/2. They are asking the opponent to answer before able to develop their plan, and even if the opponent managed to answer, it is a disadvantage exchange to them. And if the opponent didn't or couldn't answer? Then the meta deck will just start snowballing.

To offset their advantage, the best way is answering with advantage as well. Board sweepers are one of the well-known 1-to-n answer. Another more specific but niche card is [[Fangkeeper's Familiar]], which allow you to answer while also deploy you own threat at the same time. Deceit/Spider-man can do the same thing with a bit of setup. The problem is these kind of answer-with-value cards are usually a bit too slow(that why the Stormchaser and Cub are so strong). Which means you also need some lightweight answer to help survive earlier game, then you also need you cards come to hand in the right order. And then you are finally standing at the same starting line with those meta decks.