Firstly, you didn't answer my question: if the game works with a BR, how do you explain that more than the 75% of the weapons are useless in that scenary? AR/SMG starts provide variety because they allow us to use the entire sandbox, so I think the fantasy is your "reality".
Secondly, if you don't give people an option to play automatic starts, that part of the community will eventually disappear anyways, so diluting it wouldn't make much of a difference as it only affects that portion of the population.
Finally, I'll state which is the point of not spawning with it but grabbing it. In my opinion, it takes more skill to earn it by fighting with a bad weapon, requiring you to be tactical and clever. In addition to that, you must keep it smartly or either you'll waste your ammo easily or someone will steal it. If you start with it, there's no necessity to worry about keeping it and you also remove the skill needed to earn weapons (as by that way they're not worth picking up outside the power ones) and the reason to use the rest of the sandbox. By saying there are enough BR's, I'm not saying they're enough for everyone, but to allow the use of it without turning the other weapons useless.
Sure, some opinions are probably based in ignorance, but this is definitely not one of them. While Action Sack can offer "variety", it's just a random weapon start which removes any kind of competitiveness, because you can even get a rocket launcher from spawn, and they're only fun focused, so I think the ignorance is yours. Also, why do you think it only works at a low level skill? Maybe you have a different definition for it; mine and many others is getting weapons, having enough knowledge of them all to kill and controlling the map smartly, instead of just shooting with a single gun and not minding any other ways to play. Not only that, your statement which claims that any Halo is stuck with auto starts is completely false; for instance, the original Halo 3 featured it, mainly in Social Slayer , aswell as Halo 2 Classic randomly.