To me, what Danaerys really did last night was not win the throne, but rather just destroyed it both literally and figuratively. There isn't an Iron Throne, and there really isn't even a King's Landing any more.
Cersi was willing to shield herself with all the civilians knowing they could be caught up in a bloodbath.
She threw down the gauntlet by killing one of the dragons and Danys friend.
When it all fell apart she just thought about herself.
To me Dany thought no one is going to enact revenge so here i go....
Will be an interesting ending as you state there is no throne, only the symbolism of one.
Could be Jon reruns with her to her land, and honors her as queen. She sees that
it was a folly to rule people who will constantly back stab.
Or Arya , Sansa, Tireon become ruler of what’s now whatever the kingdoms are called, or each becomes its own with no overall ruler as the inter family battles should have been ended..
GOT’s entire theme has been lineage to the throne. Daenerys last comments to Jon were telling, she wanted love. The Lannister line to the throne has ended, Cersei’s incestual unborn child is dead. Daenerys and Jon’s incestual unborn child would leave little doubt as to who would inherit the throne in the future and tie Jon and Daenerys together forever.