You have not demonstrated that this is a serious and widespread problem. People have been sideloading for years without getting overrun with malware.
I use both platforms daily. I’ve been working on smartphones since they’ve existed. I live and breathe them. Android has some great upsides, but security is definitely not one of them. Six years ago at a previous employer we had cardboard boxes full of completely bricked android phones from the Triada Trojan.[0] I have never seen anything like that on an iPhone. I can’t even recall witnessing a bricked iPhone (sans hw failure), but I won’t deny the possibility.
[0]https://www.google.com/amp/s/usa.kaspersky.com/blog/triada-t...
Just a cursory search shows things haven’t improved much since:
https://news.ycombinator.com/item?id=32154294
Now provide the statistics for it.
And despite repeated claims of the loud and ignorant, you can side load to an iPhone without jail break. it does require a mere $100 a year and handful of terminal commands, but possible if you’re determined.
I’m willing to belabor your last point: the floodgates can open if all the restrictions are relaxed. One very dangerous system call[0] stands between Webkit and your choice of any browser engine. It’s not clear to me on a technical level if allowing that freedom to exploit by one app prevents any app from exploiting.
[0] https://developer.apple.com/library/archive/documentation/Sy...