In a universe with spherical cows, maybe. But the issue is that theories we view as true (at least within their scope) often fail to predict observations. Which is fine: we modify them with ad hoc hypotheses to round off the rough edges. The issue is that all theories, true or false, do that. Copernican theories were initially less predictive than Ptolemaic ones, for instance; a simple heuristic of rejecting theories that generate more incorrect predictions than other theories would have left us committed to a Ptolemaic universe. And yet we moved.