Across a large enough area it's always sunny somewhere. And clouds don't interfere as much as you'd think. Add in wind, hydro, nuclear and some gas and you can handle pretty much anything just fine.
That has nothing to do with where factories, mines, farms etc are already located. You have to buy land to connect the power plant to the load and some guy in the middle wont sell. Handle congestion/maintenance of those lines etc. Lots of issues beyond just generation that the grid already is dealung with even though massive solar plants have been built. But main thing is weather forecasting has to get better because even with existing huge plants constant surprises happen.
There's this thing called the power grid, it transports electricity across great distances.
And everything you're talking about is an issue with any kind of production, I don't know why you're bringing it up as if it's unique to solar. If you're building a factory that needs high amounts of stable power then you plan accordingly. Doesn't change the fact that solar is a useful way to generate electricity. I don't think anyone is saying we have to use it exclusively. We can use different solutions for different problems.
Lots of probs with existing grid . Certain routes are already overloaded/congested, building new ones is not as easy because of land acquisition costs compared to the past. Repairing, upgrading and maintaining old routes to handle new loads raises costs of moving electrons to your factory etc. One hurricane or blizzard can shut a route down so redundant routes have to be built. People just under estimate how complex things have become.