In the Bell System, most electronic components came in rectangular metal cans, often hermetically sealed, usually labelled "Western Electric NNNN Network". The Bell System loved inductors. Inductors don't wear out. They often used unusual inductors, such as saturable reactors, or inductors with a copper slug. For the same reason, they liked gas-discharge tubes, although they're not suitable for amplifying audio.

IBM liked plug in cards. Some cards in tabulating machines had moving parts connected to drive shafts. Tube computers had plug-in subassemblies.[1] This allowed maintenance of large machines in the field. Thyatrons were used in some early printers, as the drivers for the printer magnets. But not for logic - too slow.[2]

Everybody else had metal chassis with tubes on top and everything else underneath. Military gear would have extra hold-down arrangement for tubes, and often metal tubes, but usually stayed with the metal chassis form factor.

[1] https://www.righto.com/2018/01/examining-1954-ibm-mainframes...

[2] https://bitsavers.trailing-edge.com/pdf/ibm/logic/223-6746-1...