That's only because it's our drills. If we had started using the bolt catch, and just allowing the bolt forward by it's self we wouldn't cause the stoppage you speak of. We do the drills wrong for the rifle, against it's design. The actual bolt closure device can buy you into more trouble by hammering a round in instead of clearing it out and carry on.
OP needs to get the book "The Black Rifle" and read comprehensively. Otherwise we'll have the whole book posted here in forum. The questions and answers are simple, and all covered...no cleaning kits were initially issued. When Eugene Stoner went to RVN to find out what was happening, he was informed by the USMC there that no maintenance of any kind was being done. Yes, the wrong powder was used, fouling the bore until he couldn't see light.
Yes, waffle mags were steel and rusted in jungle conditions. The next mag was better, and then after teething problems the 30 rd came along...
The rifle that went around the world for demo was old #4 and hadn't had any stoppages that the rifleman demonstrator could remember...he'd shot a phenomenal amount of ammo through it by the end of the sales tour.