Immutable makes sense for a mobile device where you need a guaranteed way to ensure it functions as designed.
The rest is because phone manufacturers and Google (and Microsoft, et al) forsee a future where you don't control your OS, so they then control everything.
I've used Picsay for probably 10 years. My phone says it's the pro version, guess I paid for it at some point, and I must just copy it from phone to phone.
Or, it wasn't as harsh when they first appeared. I mean there was the Little Ice Age in Shakespeare's time, where the Thames froze over. If you took that as a sign it was becoming permanently like that in London, what would you do? It's not like you have somewhere else to go that you know it's better (or hell, where anything is).
People in the 20th century easily forget how little knowledge the average person had even 100 years ago. Hell, even the information the wealthy had. Just a couple hundred years ago a globe of the earth was practically priceless. They were still a luxury in the early 20th century.
I'll go a long way to reduce my data exposure, but ffs, Windows and Office are the standard worldwide, for a reason. It's just naive and foolish to fight this battle while you have enough pressure and time limits as it is.
And I run multiple Linux-based systems in my home lab, but my laptop is windows, because "ain't nobody got time for that", as Sweet Brown would say.
Or have incessant meetings with Senior management or Business Unit leadership to keep them in the loop or even constrain their unrealistic expectations.
And being a Google app, which means it can access everything.
I'd sooner use a regular SMS app, and not reward their behaviour. Which is what I do. You want to use garbage like SMS or RCS? Then you suffer the issues that come with SMS.
Hahaha, they're just now noticing? Rich.
And how will Bkuesky be any different? It won't.