Well we can talk theory or we can hobby history. How well has the open ecosystem on computers worked for the average consumer? Viruses, malware, ransomware, adware dozens of toolbars on their browser, programs randomly uploading their contacts, etc.

I know plenty of people who won’t download random apps on their computer but will on their mobile devices. Because they have had bad experiences before.

Nobody wants to force people to download apps from untrustworthy sources or to ban app stores.