> How much of that expense is based on endless lawsuits from environmental groups and weaponized environmental laws? Why can the navy without those restrictions build safe reactors for ~$2million/megawatt?

Fundamentally, unless you know the Navy's answer and can apply it to override those lawsuits, it doesn't matter: politics can't be wished away just because the wrong people have power.

> The current fallback for when renewables can't meet grid demand is burning natural gas in modernized grids and coal in grids stuck in the 1800s.

Increasingly not; as with all things, you have to aim for where the ball will be rather than where it is, and for this topic that implies that for any given proposed new gas (or nuclear) plant you have to ask about the alternatives, which also include "how fast you we build energy storage, and what would it cost?"