Not with infinite regeneration. Just look how a normal Dota match plays out.

You have argued yourself into a corner. It happens.

Salves are not infinite regen and regen-heavy deathball strats with high sustain have been a thing in the past. Calling it unfamiliar makes it seem like it's a completely foreign, unexplored strategy.

That's not the point. The point is that the humans wouldn't know that regen-heavy deathball strat is optimum unless they've played that game a few times. Since multi-invincible-courier game was not available to the casters, they couldn't really prepare for it or even had any incentive to. They were paid to just play a game, not to win it, and thus they played standard Dota 2, and didn't bother theory-crafting strategies for how to optimize this weird subset of Dota.