Yours is a proper question as to why manufacturers
don't make it 'right' in the first place.
Most try to, in my opinion, but some fail in their
efforts. Costs and royalties must be factored in
In the case of couplers, Kadee has long been the
quality leader. Other makers wanted in on the sales.
Patents required they not infringe on Kadee designs so
they had to create their own. Loco manufacturers,
such as Bachmann, get the couplers they use at
a lower price than they could from Kadee, thus
a 'less than right' product. As we have experience
with some of those we note that they are less than
perfect. That's when some of us go back to Kadee
and replace those imperfect couplers.
It's the way commerce is, and not just hobby products.