1) Your browser is always open, whereas you need to close your current app and open the app store app
2) Google Search is better at giving you what you want in the fewest number of keystrokes than any search from any other company including app store search boxes
3) installing a "web app" is one click after the google search results or if someone posts a link. As you might know from social media, even one click is a lot and most people won't click links in a comment. In the apple app store i have to tap on the app in the search result, tap install, double click the lock button, scan my face then wait many seconds. Some websites load in many seconds but that's not that common and it's considered a bad website
4) software is reinstalled on each use, meaning it's always updated. Native apps update randomly with a big delay and I have to check if there's an update manually sometimes
5) with native software there's a risk it will not support your device. Risk is commonly expressed as a cost, so the fact that in my life I've searched for an app and found out that it's not supported on iPad or not supported in my country can be counted as every single app store download since then took me .1 seconds longer because I now know there's a risk I will waste my time looking for the app. Web apps also don't work sometimes but it's more predictable since it's usually tied to real limitations like the screen size of your device. Another risk is malware, I feel nervous and powerless when installing native software because I don't know who I'm giving access and to and to what, whereas I understand what web apps can track. and also the fact that it's HTML and JavaScript instead of opaque assembly instructions makes ad blockers possible and cheap
Installation is an integral part of using software, and a big the reason the web won and continues to win.