Why not make all clubs except the driver the same length, lie angle, and swing weight for consistency?
Nobody says you can’t. Some are doing it. Was done many years ago as well with the EQL model from Tommy Armour, which had limited success. There are trade-offs in everything you do with specifications in golf equipment. If you make all the clubs one length, say 37.5″, the clubs that would have been longer will have to have the headweights increased to achieve the same feel, and the lofts will have to be decreased in an attempt to achieve the same gapping in distance. If you strengthen the lofts, you are reducing the bounce angle, so the clubs become less turf friendly. Obviously, if you start from scratch with a design for single length you can fix this in the design process, but taking an existing set and modifying will effect the sole angle in a negative way if you strengthen the lofts. The shorter irons you would have to remove weight from the head to achieve the same head weight since you would be making them longer than traditional lengths. You can also fix this in the design process if you were designing a set for single length. Longer short irons could present challenges for some, like less control, but could provide more distance in the higher lofted irons, if that’s something you want. There has been a ton written on this recently due to the success of last years US Amateur Champion using a set. Each individual has to determine if this kind of non-traditional set is something that might work for them. We have no plans of developing a specific set design for the single length application.