[jacquesm]

Wind energy economics favor: fewer blades (though the three bladed design has some mechanical properties that make them the default choice), larger swept area, horizontal axis turbine (even though you need to aim those at the wind nobody has been able to produce a very large VAT that survived for even a short amount of time), direct drive (because gearboxes are very much prone to failure).

1000 small windmills would not be commercially competitive with a single large machine, would not extract as much power from the same amount of wind and would not be as safe. Small machines have to make a lot more RPMs so are inherently higher maintenance (bearing wear), harder to operate when connected to the grid and so on.

I'd love it if that weren't the case (which is why I built my own 5 meter/16' machine) but ultimately wind power will be dominated by several MW behemoths.