This is how I travel 99% of the time, but every now and then even the best packers have to check something. Maybe it's work equipment that is just too big for a carry on, or maybe your wife bought too many souvenirs on vacation and you can't figure out where to put them alongside clothes for 2 weeks across four countries and multiple climates, and the now-expanded carry-on is no longer carry-on-able (in these cases, the remaining carry-ons contain all the souvenirs and valuables, and the checked bag contains nothing but dirty laundry, usually with an especially stinky pair of socks on top).

And anyway, passengers *should* be able to check their bags without an overwhelming fear that their stuff will get pilfered. In the safest of worlds I still would not put electronics or valuables in checked luggage, but I do like getting my clothes and suitcase back when I check a bag. Glad that there is some attention being given to this.