The user doesn't really care about the scale, though. There are chrome plugins, local apps, etc. With dropbox and other similar tools, you can sync across devices and keep configuration stored in the cloud without much hassle.

I'm not saying that what feedly was doing was trivial. I'm sure it was expensive and required many developers, designers, etc. However, that doesn't mean that all the effort is necessarily important for the end user.

I run one at scale, it doesn’t need to be done in a complicated way

What I’m saying is by running so many heavy services in the backend, relying on a series of API integrations to provide service and taking custody of swaths of sometimes sensitive user data, they make their own problems