I learned to build bicycle wheels when I worked at Jimmy Yee's Bike Shop on Queensbury Street in Boston. I built racing wheels for myself, friends, and teammates.
Agreed on machine built wheels. They are a compromise for the masses, and usually work out fine for most riders that use them within their limits, which are, of course, rarely posted. As for staying in true, then and now, pre-stressing and hand building are a factor, especially now. Back then, I was building tubular wheels with butted spokes for light weight, and straight spokes for strength. Those rims were narrow and light. High spoke counts were the norm. Nowadays, tubulars are specialty wheels. Clinchers advanced to the norm, with the bleeding edge being hookless. Minimal spokes at very high spoke tension is standard, and aero flat spokes are common. Carbon has succeeded alloy as the rim material of choice. They are built to be compliant radially but very stiff laterally, which shifts all of the stress load to the spokes and hub flanges. Keeping a modern wheel in true laterally is harder these days, no matter who built it.