'regular people' don't complain because even know about the most of the poorly thought out features of the OS. the tech-minded know about the rotation lock and the app switcher and complain that it sucks. 'regular people' find the OS so confusing that they probably never stumble on the multitasking in the first place.
Look let's stop pretending that the unsophistication of 'regular people' is some justification for the stasis of iOS. fwiw Apple was able to make huge UI changes to their iPod line over the years and didn't suffer too much (if at all) for it.
calling bullshit here for a couple reasons.
1. anecdotally, everyone I know who has an iOS device, from friends to my younger siblings, know all about the double tap shortcut to access recently used apps. I never had to teach them about it either.
2. the double tap isn't necessary for apps to take advantage of system multitasking, anyway. yes, it's a nice shortcut to switch between apps but Apple designed the system so that the user can just hit home and tap the app icon to switch apps. the freeze states and background processes work in the same way whether you double tap the home button or not.