(yes yes this is satire)
European DPAs aren't getting enough funding to take on this problem, but they haven't been sitting still either.
I assume this was how it was intended to function, but the kind people that run internet websites intentionally made it more difficult.
Lots of smaller players still do it, though, so maybe this is not the most effective enforcement style.
The sideloading of apps will technically be an apple approved app but enforced by another app store. To put it another way you would not be able to randomly download an unsigned app.
Of course if one's smart enough to only download apps from reputable websites, then the only worry will be privacy issues which are probably not important for most people
A few years ago this was an issue, when millions of macOS users found that they couldn't launch any apps at all on their Macs, because Apple's OCSP servers were down[1].
It's not a technical change in who distributes the software, it's a radical change that results in developers being able to give apps to users without being in a contractual relationship with Apple period.
IMO, https://zerodium.com/program.html is a good indication of "what would it cost to hack me using a never-before-seen exploit".
While possible, it should be more rare. When working on massive platforms it is typically the goal to minimize metrics like malware installs as opposed to trying to make them 0. The relative probabilities are important.
Compared to an antivirus (macos, windows, android, all have protection built-in), that could detect a malicious app, or receive a report about a malicious app and then block it from being run, having an app store in the chain might not even be that much help or be at all different in that process.
If anything, giving potential malware apps a chance to be published on an app store, get that scale, visibility and access to an audience outright, and hang there even if for a little bit before getting taken down, could be kinda worse than if malware apps were distributed across smaller venues. Where, through what channel could a malware app get access to biggest amount of people? Through a centralized app store. (especially if it's the only one on the platform, and the only way to install apps*, forcing all users of the platform to be there.) An app store gives potential malware makers access to an existing audience, ready to be exploited, and a centralized app store ensures that it's the biggest audience possible.