moderate primary opponents = non existent.
The “moderate primary opponents” you describe have slowly migrated to the GOP over the years. That brings a whole different set of problems, of course.
Socialists vs far-left extremist socialists were the majority of yesterday’s primaries here in GA.
Most of the far-left socialist-communist-homosexuals won.
The other tactic is running a democrat veteran lefty-pretend-conservative as a “defense expert” national security platform. Who promptly becomes an ultra-leftist socialist standard democrat voter-for-Pelosi clone.