The Lost Solar System

In earlier sf, solar planets, both known and also even unknown, were inhabited. There were:

Wellsian Selenites, ERBian Moon Men and Lewisian moon dwellers;

five extraterrestrial solar races in Heinlein's Future History;

the eccentrically orbiting planets, Mongo and Hesikos;

Vulcanids on an asteroidal Vulcan and beast-men on the invisible Varang-Varang in William Dexter's two Denis Grafton novels.

In more recent sf, Terrestrials are the only solars.

Poul Anderson, transitionally, has:

no native moon-dwellers or unknown planets;

Venerians in one earlier short story;

several Martian races.

The Martians in "Margin of Profit" were edited into extra-solar colonials when that story was rewritten to fit into the Technic History.