My assumption would be that those tables which ignore material components in general don't ignore the expensive ones that serve an obvious rationing purpose.Both spell component pouches and arcane focus/druid focus/holy symbol exist. You can completely ignore it for all normal play, so ignoring it gains you absolutely nothing. THERE ARE NO GAINS TO IGNORING JUST MATERIAL COMPONENTS.
But there are losses. Such as non-caster foes "disarming" by taking weapons and material components but not realizing that leaves some spells possible for clever players for the once-a-campaign jailbreak. And looking for scavenged ones - some spells like Sleep or Spider Climb they might easily find the components.
And as mentioned there is a separate design purpose for expensive components, and stripping that away willy nilly without giving thought to the changes that will bring is also a bad thing.
So yes, I can believe you that some can ignore just material components. But since that's a worst-of-all-worlds solution with no benefits and some detriments, I hope that's rare.
And I don't think the losses you point to are very severe. Material components are not a part of B/X D&D, do not generally figure in 4e (outside of the context of residuum costs for rituals), and are absent from other FRPGs I've played (eg Rolemaster, Burning Wheel, Torchbearer other than as buffs). The benefits of opening up scavenging or captors who are ignorant of spells with only V, only S, or only VS components, are in my personal view outweighed by the inanity of treating the spell component pouch as an endless bucket of cobwebs, guano, shards of amber and the like, and by the work of actually tracking them.
So I, personally, do find gains in an approach to spell casting that ignores them, and that uses simply words or gestures (or both) as the baseline for spell casting.