Because it's inevitable at a certain scale.

The brand has a momentum, even if things start getting worse for customers there isn't an immediate response on a large scale.

A certain quality is important for the "true" advocates, but we're a small minority. Growth is driven by at scale customers who don't notice these issues because they're buying the products for different reasons.

In this context, improving quality to keep the hardcore fans happy costs money, but doesn't impact the bottom line significantly in the short term.

Growth is the only goal at this scale and that's driven by other strategies and not hardcore fans.

I guess long story short is corporations are cash machines and product quality does not play an important part at this scale.