MC34063 Switching Regulator IC: When was it introduced?
The 1983 edition of Motorola's "Linear and Interface Integrated Circuits" (Series D) catalog contains an "Advance Information" data sheet for the MC34063 so that is likely to be around the time of introduction. That catalog also contains several other switching regulator ICs. Among those were MC3420 and MC1723 (below).

My first switching regulator circuit was around 1982 using an LM723 (National Semiconductor) which could be used as a linear or a switching regulator. This part was also available from Motorola as MC1723.

Both the LM723 and the MC34063 are still available!

In 1968, Motorola published "Semiconductor Power Circuits Handbook" which contains several discreet switching regulator circuits. We have a first-edition copy where I work ... a nice little book.

For more on the history of switching supplies:
https://en.wikipedia.org/wiki/Switched-mode_power_supply#History