1) I've been through shortages at least 3 times in the last 25 years, it has taught me to plan ahead. Last winter my wife and I put on average of 200 rds a week, each, down range while all I read was whinning about shortages.I get what you're saying, but some considerations from my perspective:
some thoughts, not an exhaustive list. I haven't seen what I'd call radically difference results in ammo lots. I've seen some, but generally not enough to make any practical difference for hunting or training. It would make a difference for competitive shooting, or longer range shots beyond 300-400 yards (rifle).
- availability - can't always find ammo or there are restrictions on qtys
- budget - may not be able to afford to buy in qty
- for some, the amount of variance between lots isn't readily apparent to the novice shooter - but it is still adequate for practice and defensive use.
- spouse friendly approach - buying here and there is usually more acceptable.
2) Budgeting is one of those topics unfortunately taught in school any longer. When you talk of prepping as a lifestyle your budget planning should cover 365 days not 30.
3) I have 3 rifles that shoot .223/5.56mm. 2 of those rifles give me light primer strikes using cheap Chinese Norinco ammo, it works fine with the third. Consistency and reliability is exceptionally important.
4) I'm the guy who had to buy my wife 11 different guns, until she found the 7 she wanted to use for competition.
I agree that for short range use, under 75 yds their is little difference for a novice, but I currently live in the prairies.