I mean, the early 70's saw some incredibly pivotal policy changes.

The US ended its trade embargo with China. The US dollar flooded European markets. The Vietnam War. The 26th amendment to the US constitution was passed, lowering the voting age. Women really entering the workforce.

Also, president Nixon announced that the US will no longer convert dollars to gold at a fixed value, and with this, froze wages, prices, and rents for 90 days.

Many things can point to this crucial economic change that all culminated around 1971.