All nonsense. The “general welfare” clause in the Constitution preamble is one such sufficient authority. As for the big fire in Savannah in the 19th century, the one I recall occurred in 1865 during the Civil War (no this one was not set by Sherman’s troops!) when Georgia was still in secession and did not even have representatives in Congress: Congress’s reaction was perhaps not very benevolent, but not at all surprising under the circumstances.
Many diverse judicial interpretations of the authority granted the Federal government have arisen and often broadened over time, ever since the Constitution was written — even without explicit Constitutional amendments. This was natural and inevitable as the national economy developed and new needs became apparent — especially after the Civil War, the development of railways, and as a result of experiences with regional natural catastrophes, the suffering caused by economic depression, etc. States themselves often welcomed these developments, as their own resources and tax base were limited.