A better lesson to take here is second system syndrome [1]. JWST took so long because it was so ambitious. Hubble has a 2.4m mirror. JWST has a 6.5m mirror. No

A better lesson to take here is second system syndrome [1]. JWST took so long because it was so ambitious. Hubble has a 2.4m mirror. JWST has a 6.5m mirror. No rocket can launch that fully assembled so you've automatically added a bunch of complexity to unfurl and assemble that in space. There's a whole bunch of other new things that simply have never been done before. Any one of these is a challenge. Doing them all at once with almost no margin for error and no possibility of intervention and repair drastically increases the complexity and cost. Another example: the instruments are so sensitive that after fairing release it has to be rotated to keep them away from direct sunlight. That'll continue on the journey to its final orbit. Also the sunshields are tennis court sized. It is mind-bogglingly complex. Arguably what they should've done is launch something slightly less ambitious sooner. [1]: https://en.wikipedia.org/wiki/Second-system_effect https://en.wikipedia.org/wiki/Second-system_effect