But you will still need to maintain a grid that's sized to handle situations when there's no solar.
The biggest issue in germany regarding grid and renewable is a distance of 800km between north germany which has a lot of wind and south germany which has a lot of solar.
Diverge it a little bit better and no issues
The grid which connects the Suncor Fort Hills mine in Alberta to Tijuana in Mexico.
Even if you want to expand that grid to the level of everyone getting their winter midnight electricity from the midsummer sun on the opposite side of the planet, the material element of the "electric highway" isn't what stops it, it has a low cost compared to the last-mile stuff that already exists.