** And if the ratios used in 1790 still applied today, we’d have thousands of Congressmen. *That point is meaningless. The 435 cap is legislated as a total number of seats, NOT an allocation per X hundred thousand population. * You start from the total THEN divide. If half the US were wiped out tomorrow Congress would still add up to 435, they’d just be redistributed in the next census.
Besides, the 435 cap was not passed until 1911 for the admission of NM and AZ and the Constitution mandates the least populated state to get no less than one Representative, so before 1911 the practice was give the handfull of smallest states one each and then add multiples from there on the cap was enacted when they (a) realized mass immigration was creating a population boom that could conceivably lead to some states having hundreds of seats if strict ratio were applied and (b) thought they were done adding states, having “filled in” the continental states.