Romas are good if properly ripened . . .
. . which is rare in many regions. Their primacy for sauces is based on the ratio of flesh to seed mass - they are very fleshy.
To quote one of the largest tomato barons (and political contributors) in Florida, as quoted in the Wall Street Journal some years ago, "Who cares what a tomato tastes like, they're always served with something else".
Incidentally, one effect of his political contributions was a law passed by the Florida legislature to require a particular type of packaging for tomatoes - a packaging that guaranteed actually ripe tomatoes from Mexico would be destroyed in transit.
