I think a huge factor I haven't seen mentioned is continuous delivery. How often were new operating systems released? How often were new products announced? When you bought software, the devs would be hard at work working on the next version with the incentive to make it good enough that people would buy again.

Now software is continually released. "Major" updates are expected every year, and they're often free and people are expected to upgrade. Subscription models have rolled out, so while directly interacting with your customer probably leads to a better product, there's less incentive to re-invent the wheel - you don't need to upsell all your previous clients.

I would assume that all of this is leading to better products, but all of the baby steps make it all seem so lacklustre.

For example, compare the iPhone 13 Pro's camera to, say, the iPhone 8's camera. Had Apple waited 5 years to release the upgrade, the new camera would have blown. peoples. freaking. minds. However, since it's been getting slightly better each year, we instead have people complaining about how the only difference is a slightly better camera.