Nobody would force you not to continue using the Apple Store or maybe an even better store with even better reviews and with an actual quality static analyzer. Apple fans will say that evil apps will go to the bad App Store, then this would be a great news for you and if for some reason a super quality not evil app will not be on the App Store you can then ask yourself why good apps don't want to.
For sure you will get the option to install a numberous number of GPL software.
There is nothing Apple needs to do to 'protect' you: people are buying the app, it's probably doing something well.
Apple is just milking the developer.
"Useful" is a huge stretch. I tried the game "egg, inc" this weekend and one of the mechanics forces you to view adds for other apps, and it's all addiction mechanics with an indecent 'skin' on them.
For example, there is one bejeweled-like game where there is a king who is being tortured, and you must make matches at speed or the spikes are driven into him, or he is forced to pee himself. There is another 'match two' like game where your reward is to take a female character and shave her head so she acts ashamed, and then dress her in streetwalker clothing.
Ultimately, Apple (and Google) have incentivized developers to make terrible games full of ads. Perhaps that is a larger problem that requires a broader, more systemic solution.
Similarly, when I put my user hat on (as opposed to my SWE hat) I appreciate the curation, at least compared to the Wild West of downloading applications off the internet.
But the impact to global productivity is substantial. Less innovation occurs. Less energy to try new things. Money doesn't spread as widely as it should.
For example, take this dumb phone[1]. It is powered by a Mediatek processor whose IP is freely shared. The innovation that resulted is not something better like an iPhone. Instead 1000s of different shells or an additional button here or there.
[0]: https://hackaday.com/tag/mt6260/
[1]:http://bunniefoo.com/fernvale/fernvale-phone-spread.jpg
I guess this scenario might be a bit different since we are talking about software...but i'm not so sure.
To be clear, my assumption are based on what I read about developer houses like this. Sometimes (though it is rare) their accounts are getting closed on App Store and they hit the news.