What was the major financial change between post-world war ii borrowers and borrowers after 1970?

Two oil shocks, an expansive monetary policy, and growing competition as Europe and Japan recovered from the devastation of World War II.
By the end of the decade, the country went into what came to be called
stagflation, a combination of no growth and rising inflation. In effect, the country had the worst of both worlds.
President Carter’s appointment of Paul Volcker as Federal Reserve Chair started the path to change. He restricted the money supply in a war that drove up unemployment but eventually tamed inflation.
The Reagan presidency started with cuts in spending and income taxes in what was called a ‘supply-side experiment.’
The intent was to stimulate saving, work, and investment. The emphasis that the supply-side approach put on incentives is now a more prominent part of economic thinking, but the experiment itself led to larger fiscal deficits.