The 2707's cancellation being the reason for Boeing laying of 60,000 people is a huge exaggeration. There was a general downturn in ALL airliner sales at that point in time in the 1970s, affecting the volume of existing subsonic airplane production.
The SST contract was cancelled in March, and the sign went up in April 1971, the same month that Boeing's workforce reached the nadir of 38,690.
The energy crisis didn't really bite until 1973. [0]
http://old.seattletimes.com/special/centennial/november/ligh...
Read more history about the 1970s oil/energy crisis.