The point is that smartphones were a niche product until the advent of the curated app store model. People were used to computing devices being flaky and something that ‘techie people’ sorted out for them when they got viruses or slowed to a crawl or otherwise failed on them.
With the advent of application delivery platforms on smartphones, people could easily browse, pay for, install, and update useful applications without it falling apart when it got infected with trojans etc. It was a major step forward for the usability of consumer computing devices, the user experience on smartphones for a non-technical person was so much better than a Windows PC they had to do something about it. I don’t really see how anyone can argue that a trusted application store and update mechanism isn’t better than the old wild west were people just downloaded .EXEs from random websites and prayed it was clean.