> make money on ads on the web?

well yeah, but a local app can get a more detailed fingerprint off the user, which includes location visited, app installed, habits etc. an app can do a lot more things when installed and closed compared to a closed browser tab.

> the Yelp app I don't get any ads

the profile is sent upstream and aggregated. ads served from other apps and on web pages you visit have a chance of using information collected by yelp even if yelp itself is not showing the ads, that's the point of it, a seemingly innocuous "ads free" app collects telemetry and third parties use that info to build a profile and serve personalized ads on other apps and web pages, correlating sidechannel info (last seen position, ip and other) to unmask your browser/app session and pin it to your "shadow identity" in the advertisers' system.

Also the app can send notifications to force re-engagement.

There's been a lot of press here and otherwise lately about how lucrative mobile data is and how lax the permissions can be, particularly compared to "just" a website.

The app can also do things to fine-tune your advertising profile like track your location in the background, etc.

Yup

Ignoring advertising for a moment, mobile apps are first-class clients, whereas mobile websites frequently aren't. Mobile websites are usually stripped-down experiences, and the company doesn't want to invest the effort in turning the mobile website into a first-class client because most of the users are on the mobile app. It's easier to just funnel people into the app, which is also much more likely to get the user to come back (now they have the app on their home screen, the site can send notifications, etc)

That seems entirely circular. The mobile website is poorly made, so people use the mobile app, so the mobile website is neglected. I can understand why the mobile app gains dominance after the cycle starts. The question is more why this cycle starts.

People are going to use the mobile app regardless. It's the first-class experience for mobile. People don't use the app because the website is poor; people simply use the app.

Or to put it another way, Yelp would be rightfully lambasted for not having a mobile app. Having a mobile app is table stakes for a site like Yelp. And if you've got all this engineering effort going towards a mobile app, why double your workload by also building a first-class mobile site? The mobile site just needs to be functional enough to satisfy the basic needs of casual users.

I think that was my main annoyance when Google removed the "merge tabs and apps" feature in 2016. With that feature, a shortcut to a webpage was a first-class experience that worked nicely with the app switcher.