For someone who can't imagine that email may sometimes come from people who doesn't have their best interest at heart, sure.
Me, I receive 5-15 spam emails a day, which are filtered only by my local mail client, with some false negative, and extremely rare false positives (I spotted one in several years, and I always look through my spam folder).
Despite my lack of Google grade filters, I can use email just fine.
Windows is a minefield to download for.
Linux is a yum or apt away.
And iOS is antiowner garbage.
MacOS is targeted a bit less than Windows because its user base is smaller, tends to be a bit more technical, and running arbitrary apps while allowed requires magic incantations like right click open (twice) the first time or opening a terminal.
Every non technical person I know loves iOS because it just works and doesn't rot from malware or badly written apps that trash the system.
Never ever underestimate what people will do for even mediocre amounts of money. Look into the enormous ecosystem (bordering on a subculture) that exists around click fraud and other forms of ad network abuse, or try to search for some Windows software and look at how many fake sites you get. It's unreal. There's money to be grabbed, so it gets grabbed.
or even just for thrills or for nefarious purposes!
Reminds of me of that backdoor in Notepad++[1], an app many developers I've worked with used.
[1]https://www.hackread.com/wikileaks-vault7-cia-docs-notepad-p...
You are missing a major issue here: spam. E-mail and phone calls are riddled with spam precisely because these are at least somewhat open systems.
E-mail is unusable without running it through a ton of spam filters or (more commonly) letting someone else with a larger data set do that for you.
Phone calls are in some ways even worse. I no longer answer unidentified calls, period, and I keep my phone on vibrate at all times. Any important calls must be scheduled. I get 2-4 robocalls per day. I'm tempted to change my number but I've heard it doesn't matter.
Spam is a huge reason walled gardens win. Anything open gets abused to death.
Another example is closed OSes like iOS. Consumers love iOS because you almost never see malware. Open OSes easily acquire malware if the user is not tech-savvy (and even sometimes if they are), and finding software outside a walled garden is an exercise in picking your way through a minefield. Have you tried to search for a Windows app on the open web recently?