Yeah, they really can't finish that, they still have fortification, and Luna is still there. They should not force the throne where the consequence is they will be wiped out, that's the mistake I saw from them because after the wipeout, it's already done, Tundra is already above and steps ahead of them.
But maybe they really forcing to finish as early as possible because they can't able to handle Luna anymore in late game? Which I agree also if that.
I had to look back at the highlights after Tundra lost the fight there was a lot of time, and the respawn timers were around two minutes. When Willow and Invoker were the only heroes alive from the side of Tundra they bought so much time after they tried to pick off Rubick near their outpost and spent 20-30 seconds to punish the Willow.
They still had the firepower to handle Luna as long as they threw everything on her, they got to run her down in that one late game fight around the Dire secret shop. During their final push, the Elder Titan ult on top probably caught them off guard.