It happens to me all the time and has been moaned about on these boards constantly (by other folk). Reloads, reloads, reloads. Nothing to do with my installation, it's relatively fresh.
I'm just giving the folks here an example how my 5S works perfectly fine - not "crippled" at all.
All for additional RAM in future iPhones. But "crippled", "necessity".....you're overstating.
How about killing some apps in the multitasking tray? I periodically kill apps running so they don't continue to use up resources needlessly. It's not a difficult thing to do - do you leave dozens of apps open on your desktop or laptop constantly?
Would 2GB of RAM improve the iOS experience? Perhaps, though I would still argue a majority of people wouldn't notice - but for those of you who do and complain about it, it would. Is 2GB+ an absolute NECESSITY that would make the 5S USEFUL and not CRIPPLED? No....not by a long shot.
EDIT: Side-note, I notice more people complaining about this issue related to the iPad Air.....on which I have noticed reloads with no other apps running. I wonder if it's simply a bug in the iPad version of iOS - perhaps Safari on the iPad handles things differently.