How come only 1 or 2 cartridge makers offer a tune-up after run in?

Analog expert Brooks Berdan always broke-in the cartridges he sold and installed on his customers’ arms, not letting them leave his shop "in the box". After running the cartridge for a certain number of hours, the cartridges suspension having been fully exercised and stabilized, he would then do the set-up all over again. That’s the right way to do things, but is uncommon.

Sure it's great that Brooks Berdan adjusted the setup after a cart's suspension is broken-in, but isn't that different than what VDH does and actually opening up the cart and adjusting the suspension, rechecking channel balance etc. inside the cartridge itself? 
I also have owned a number of VDHs, agree with OPs observation that the adjustment or "tuneup" does improve the sound and was curious about other cartridge manufacturer's viewpoint(i.e. why it's not their practice) on that idea.Cheers,
Spencer

Perahps, there is better QC with modern cartridges which negates the need for a follow up tune-up, or there is not enough cartridge artisans within the manufacture to perform a follow up tune-up.