I think the 2:30 was the time mark, not the time it takes to take down the tower.  A level 3-4 oak with spirits and monks can take down the tower in probably under 30 sec if left alone.

If you die, you might not be back in time.

Oh, certainly, if they leave you alone, a Rook can easily take down a tower. I was assuming that both teams have equal skill, but one player made a mistake and died early. In this scenario, it isn't likely that a tower would fall early game. However, if all 3 Demigods are in the lane, the tower is toast.

Could someone please post a replay of a game where someone did not die first.

It's not even that. it's that it so easy to level up early, that if you die at one, you come back out to the field at 1, and the enemy is at 3 approaching 4. Once they hit 4 its bite 2, spit 2, penitence 2, etc. Then you really get messed up if you try to hold a lane. Since you can't hold, you fall back, and lose more warscore.

Honestly, in my experience, the opposite is true. Maybe it is because I play n00b games, or maybe it is because I'm bad, but dying early is much better than dying late. If you die early, yes your opponent who knows how to play might have the tower down before you respawn. However, as you grow in level, you are going to take longer to respawn. If your opponent might have your lane's tower down before you respawn in the early game, he is definitely going to have that tower down in the mid to late game. Also, with no creep reinforcements in play, your opponent is going to amass XP much less in the early game than the late game. Since you are respawning (relatively) sooner, you are going to be (relatively) less behind on your experience.

An early death is not necessarily the mark of death, and I too am annoyed when someone leaves within the first minute.