for software design, i'd expect that launching the app store played a big role.

the app store ceded a lot of the experience to other developers that apple couldn't control or hold to their standards, so it's not a surprise that they responded by just kind of giving up and chasing flashy aesthetics in order to compete.

it's one thing to belabor every little design detail when you know that you are shaping a holistic experience, but if you know that the user is going to spend half their time using some janky app that you didn't make, it's hard to convince yourself to spend a ton of time making your half better.