A fictional universe of battletech illustrates that quite realistically.
They have fusion reactors for every housewife, godlike metallurgy and rocket engines, but they can't make advanced computers no matter how hard they try after an interstellar nuclear civil war put an end to interstellar trade and, thus, complex economies and long supply chains.
Such things require enormous societal organisations to work, and that requires period of civility, prosperity, and material security to make people with brains to do things like that and not to scramble to work on better bomb shelters.
After few generations of people living caring about only basic necessities, the society went into downward spiral because the less scientists and engineers there were, the less were available to teach the next generation of them, and maintain advanced manufacturing equipment.
Despite the basic knowledge of science still being there, there were nobody with hands on skills and material capacity to make complex manufacturing equipment even after a period of relative prosperity 300 years later.
It's like asking a average random engineering or physics PhD to make AMSL 3500 EUV scanner. He will have a basic idea how the thing works, but it will take him more than a lifetime just to make a single part of it if he were to work alone without societal and material facilities for making something so complex.