I know it's not much but Tied and Soldered wheel spokes = Solder = lead = weight......on the last place you want it on. So even in the ever-so-weenie 80's I suspected that tying and soldering wheels is just mostly oldtime bikie folklore, similar to the thought that those goofy old leather hairnets were supposed to protect you in a crash.
As for retaining spokes in their place if they break or for replacing damaged rims, I'm cuurios if a small dab of clear silicone could do the same job, but in a more "modern" way and not to have to mess with fiddly wire tying and soldering tools??....but I'd rather not mess up my wheels with it anyway.

Chombi