[niemandhier]

There are specialized companies selling components, what you cannot get you manufacture yourself. Assembling the device for prototypes like this is usually done in house.

Established labs often have a specialised section that cultivates all the little tricks how to do these things.

Knowledge is transferred by hiring postdocs that have the skills you need or by sending a phd student over to be trained.

As a scientist, if you do this for a while you end up with insane skills, but there is no place for them on the job market.

Everybody else is living 15 years in the past from your perspective.