Many companies went public in the 1970s due to high inflation and taxes, which made entrepreneurship and raising capital through public markets more attractive than traditional employment or debt financing. Specifically:

1)High income tax rates, with a top marginal rate of 70%, incentivized entrepreneurs to start their own companies rather than work for someone else and pay exorbitant taxes on their income.

2)Rampant inflation, peaking at over 11% in 1974, eroded the real value of debt and made equity financing more appealing.

3)Companies could raise capital by going public without taking on crippling debt burdens.

4)The stagnant stock market of the 1970s, with the S&P 500 returning just 17% for the entire decade before adjusting for inflation, drove bright minds away from traditional corporate jobs and toward entrepreneurial ventures.

Regulatory changes like the end of fixed commission rates in 1975 made it easier and cheaper for companies to go public.
A prime example is Walmart, which conducted its initial public offering in 1970 to raise capital for expansion after accumulating too much debt from bank loans. The IPO allowed Walmart's founders to pay down debt while funding further growth through equity rather than more loans. Many other pioneering technology companies like Apple, Microsoft and Oracle were also founded in the 1970s.