Android

Google loves to merge apps into one so you are forced to use the rootkit virus that is the Google app.

It's a consequence of Android, but you can use GrapheneOS if you want to break away.

What if you install an older version of the Translate app?

I use Google Lens and I also have to keep Google app installed. I agree it's annoying that they just can't make the apps work standalone. There already is a package that nearly all Google apps dependend on. The package is Google Play Services. Why can't they implement this into Google Play Services as they do with all the other stuff (quick share, find my phone, location services etc...)?

Try DeepL app instead

It's part of the never ending death march of every decent Google product.

First it's a name change, then they'll tweak a core functionality so it's really really helpful, then they'll either kill it immediately or move it into another package (thus fracturing older apps and devices from the functionality completely), then they pay wall it or kill it abruptly.

~~Honestly, I'm kinda surprised that the live translation in Google Camera wasn't dependent on other Google apps before - I thought all Google apps were developed with the assumption that the apps mandated for Android certification would be available, and that losing functionality if the user starts disabling stuff is fine.~~

As to why it isn't very common: Android conditions users to think of the apps as fully self-contained units. There's no way to have Google Play suggest installing app B as an optional dependency when you install app A, and asking the user to install it during the first launch would go against common user experience wisdoms. The current best practice is to get the user up to speed as fast as possible, with every extra tap they have to make increasing the possibility of them leaving for another app.

But there are definitely apps that do use this. For example OpenTracks, a GPS tracking application, has no integrated map to show captured routes and instead expects the user to find another app that supports its API. Or GadgetBridge, an alternative companion app for many smart watches / fitness bands - it is common for these devices to have some weather forecast widget, but one of GadgetBridge's design goals is to not to have internet access (to help with trust). So it has an API for weather provider apps to make this work.

Edit: First paragraph is toast, I misread the OP

Buying the Google Pixel and getting upset that it needs the Google App to fully function seems silly