I'm not sure if the real Ziplocs are better built, but of the 10 bags I found and used here in Germany about half fell apart (as in broken beyond use or repair) on a five day trip. Luckily they waited till after use but given I opened them exactly once to get the prepackaged food out I was not impressed. There might of course be better ones somewhere, but I really don't see them holding up for even a week of daily use.
I know Aloksaks might probably work, but they're more expensive then those STS dry sacks. And it's extremely easy to make new bags out of relatively tough old PE shopping bags (not the thin ones with holes in them, more like freezer bags in very large).
And yes, it probably is in large parts edutainment, although transporting food like coffee, milk powder and couscous in a way that doesn't produce breakfast in my pack at some rainy point and is easy to use has been bothering me for a while.