The near zero interest rates, pause on student loan payments, pause on rent payments, doubling of unemployment pay, and then the dustings of stimulus checks and bonus childcare checks, all while most white collar workers just continued working like nothing happened, created an incredibly cash rich environment that most people have never seen before.
And the PPP loans handouts to business owners just to throw more gas on the fire.
Software in the US has (aside from maybe finance) been an almost uniquely well-compensated field. That will probably adjust over time especially given the inflow of grads primarily in it for the money.
Software industry was over hiring probably ever since dot-com bubble because after the bubble burst revenue and profits were rapidly growing and it never really stopped. I would rather blame the managers who constantly pushed for more workers instead of increasing the productivity of the existing workforce.