Earlier quoted context omitted.
> adding more workers to a field increases the supply of workers and thus reduces the market value of their work This is the lump of labor fallacy. If you don't have "enough" software engineers, then adding more makes them all more valuable; some of them can work on productivity tools for the rest, some of them can attract new customers, some of the juniors are needed to turn into senoirs, and so on. It's similar to…
> afford to buy the cars Maybe that is a red herring and what Ford got from higher wage was workers that cared about the work they did and made sure the quality was good, as the workers would otherwise end up in a lower-paying job. When you make "revolutions" such as the first good assembly line, workers that care make a big difference. Faults on assemble lines can be much more expensive than high wage.
Don't let the above take away from the other factors you mention. The total situation is complex.