I still don't get why people bother over apps that they will never use in their entire life.
I have Lumia 930, and all apps I need are on it. I have 2 Android devices and older iPhone on my desk (they are collecting dust mostly) and I really don't have any intentions to move on them. I am pretty much satisfied with my Lumia 930. I have everything I need: AccuWeather, Crunchyroll, Enpass, Facebook (I don't care if it miss some stupid features I will never use), Instagram, JSON Editor, Linkedin, Messenger, Microsoft Authenticator, Microsoft Flow, my bank official app (m-zaba), Nextgen Reader, Skype, Slack, WhatsApp and Uber. All others app like some games or apps that I don't have any interesting in, I don't care if it exists or not. I don't have a phone to have installed what other people likes even if I won't be using those apps.
How I look at missing certain games is like how I choose to have an Xbox One vs having a PS4. I could easily own both if I wanted access to games not available on Xbox One. However I choose not to. While I have everything I need as far as apps and for those missing, either pinned the website as a tile or I use my iPad mini for.
The problem is that for most people, owning several devices isn't something they are willing to do. For some, it doesn't work well with their use case. While I am unaffected by the app as you are, the vast majority do care about these things. Especially once they have become used to a certain work flow, it's hard to make them change.
For a large amount of people that are on these forums, we are willing to do the research necessary to find an alternative. Typical end users just want things to work and have access to things directly. I prefer 3rd party apps as usually the design and feature choices are more appealing to me. This doesn't apply to end users. All they see is, no YouTube app from Google, my bank doesn't have an app, etc and are not going to think about using the mobile website. To the average end user, if the app doesn't exist, they don't have any access at all.
PWAs should solve this issue as end users wont be able to tell the difference between a PWA, web wrapper, and a native app. This is why I think Microsoft should be heavily investing into PWA support as this will solve the app gap for many services that already have websites, assuming the web devs will make the transition as well.
It's too difficult to try to place a number of apps needed when the vast majority are spoiled with too many apps, not enough time to try them all but when they think of something they want to use, "there's an app for that." It all depends on the specific's users work flow. Take a large group of people with iOS, Android, Windows 10 Mobile, Blackberry, etc. They will all have varying apps. Some may have installed 5, some may have installed 50.
I will say this, as far as a number of apps needed, we need all
native Google services, top ecommerce apps (looking at you eBay), and for the love of God, all Microsoft apps available on iOS and Android with the trend of Microsoft apps coming to and updated
first on Windows!!!!