Since solder is such a poor conductor, why use it?

Electron tubes are not soldered into place. All those ribbon connectors are not soldered. Why not use tiny little mechanical connectors instead of solder? Has anyone actually measured the losses due to all the solder connections? One wonders how much it could be and compared to what.

Wire wrap connections...

Almarg, I doubt seriously if the solder you and I have access to is anything like that used in the military.

Mapman, a linear amp doesn't solve the problem but could afford the welding of wires.

Almarg, I doubt seriously if the solder you and I have access to is anything like that used in the military.

Tbg

I spent 20 years as an electronic tech in the USAF and there was nothing special about the solder we used. Yes I was soldering components on boards as well as connectors used in aircraft. Now maybe NASA uses something special, but I doubt it.
A good solder joint is going to last. It just has to be done properly. That's what quality control is for.

I guess the military need not use lead free solder. The EU has largely forced the move against lead in solder. Lead is a poor conductor as is tin, but lead tends to not crack. Welding copper to copper or silver to silver would mean no loss of conductivity.