Las Vegas has already achieved 97% storage supply for its needs - a city that barely sleeps at night.

Hard data is where? And I bet LV heavily relies on hydro and gas powerplants. Solar is a tiny fraction, even though, where is its energy stored?

Again, where is your evidence that it is not going to improve across the board, and will all fail?

Instead of trying to pick a fight, please read what I write: "Perhaps somewhen in the not so near future, but today?"

And it’s an especially ironic answer given that it takes up to 20 years to commission a nuclear power plant. And they are down for scheduled maintenance for up to a month a year, etc.

The difference with nuclear power plants is that we have the technology today. Can you say the same for batteries? Also you'd build a surplus of nuclear energy power plants (or have another backup plan) just for cases like you mention. The maintenance frequency varies, i.e. for a Slovene one is once per 18 months. But that's something you know in advance and one plans for.

EVs are rare (in the context of total energy consumption, even more so because not so many models offer this feature), limited to houses (what do you do when you live in a flat?) and not a reliable source - "honey, I need to drive fetch some groceries, you won't have energy in meantime". How many houses with only EVs as energy storage are disconnected from grid? I bet the number is next to 0. OTOH EVs as energy storage can provide buffering to energy grid when properly connected. This feature has its place, but they can't be used for reliable storage.