请教一个语法结构

mndd

in 1933 the rubber, clothing, and shipbuilding industries put into effect a six-hour workday, not as a temporary expedient but as a seemingly permanent accommodation to what many observers thought was an economy made overproductive by advances in technology.

what many observers thought was ...是同位结构，请问什么意思？
感觉what前面那个to，后面应该跟一个名词性从句，后面was什么什么的感觉好奇怪

mndd

读起来真的好费劲阿

aeoluseros

many observers thought是一个评论子句。
lz可以搜索一下“嵌入式关系分句”，原理上相同。